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The Ingenious Architect: How the Ruby-Throated Hummingbird Builds Her Nest

i May 31, 2024 No Comments by

This month, Wake Audubon invites you to join us in a blog-writing experiment. This Bird of the Year article for June was composed by ChatGPT-4 and edited, amended, and fact checked by me, contributing writer Brittany Richards. With mating season in full swing, and our female Ruby-throats preparing to raise their broods, I prompted ChatGPT to write a “blog post about how the Ruby-throated Hummingbird builds her nest.” I changed and added supporting details to ensure factual accuracy and to provide additional information about our fascinating hummingbirds. Please share in the comments any thoughts or feedback you have about this A.I.-assisted post. And if you prefer your articles written entirely by human beings, then you can look forward to next month when we will return to our regularly scheduled programming! 

The Ingenious Architect: How the Ruby-Throated Hummingbird Builds Her Nest

The Ruby-throated Hummingbird is a marvel of nature, not only for its dazzling aerial acrobatics and iridescent beauty but also for its extraordinary nest-building skills. These tiny birds create nests that are intricate and remarkably sturdy, tailored to the survival of their young. Let’s delve into the fascinating process by which the female Ruby-throated Hummingbird constructs her nest, a masterpiece of avian engineering.

Location, Location, Location

The first step in the nest-building process is selecting an appropriate site. Just as every aspect of rearing her chicks is a solo endeavor, the female Ruby-throated Hummingbird chooses the location for her nest all by herself. Typical sites include the slender, horizontal branches (out on the limb, and not in the fork) of deciduous trees such as oak, maple, or sweetgum (but also less frequently in evergreens such as pines), usually 10 to 40 feet above the ground. These locations are typically near a reliable food source and provide ample cover to protect the nest from predators and harsh weather. Rarely will a nest have survived the previous winter and can be refurbished in the spring. But a female may use the same tree, and even the same branch, as previous years to build her new nest. Likewise, in areas where a female raises more than one brood, she may reuse her nests, but may also build a second nest even while still raising chicks in her first! 

Female sitting on a slender branch. Photo by Bob Oberfelder

Female sitting on a slender branch. Photo by Bob Oberfelder

Gathering Materials

Once a suitable site is chosen, the female begins gathering materials. The construction of the nest involves a variety of natural materials that are both lightweight and durable. Key components include plant down, spider silk, and lichens. Plant down, sourced from dandelions, thistles, and other plants, forms the soft inner lining of the nest, providing a comfortable and warm environment for the eggs. Spider silk is a critical material, used to bind the nest together. It offers remarkable elasticity and strength, allowing the nest to stretch and accommodate the growing chicks. Lichens, collected from tree bark, are used to camouflage the nest, making it less visible to predators

Building the Foundation

The nest construction starts with the foundation. The female uses her tiny beak and feet to weave the spider silk into a flexible base that will attach securely to the chosen branch. This initial phase is crucial, as it ensures that the nest is anchored firmly and can withstand the elements. The spider silk’s adhesive properties are especially valuable here, creating a sturdy but pliable base.

Crafting the Cup

With the foundation in place, the hummingbird begins to build the cup-shaped structure that will house her eggs. This process involves meticulous layering and weaving. The female alternates between adding plant down and spider silk, molding the materials with her body to shape the nest. She uses her body as a mold, pressing against the sides to form a perfect cup shape. This stage requires incredible patience and precision, as the nest must be both deep enough to keep the eggs secure and compact enough to conserve heat.

Camouflaging and Final Touches

After the basic structure is completed, the female focuses on camouflage and insulation. She meticulously applies lichens to the outer surface of the nest. The lichens blend seamlessly with the bark of the tree, rendering the nest nearly invisible to predators. This camouflage is crucial for the survival of the eggs and, later, the chicks. Additionally, the female may use more spider silk to reinforce the nest and ensure it remains securely attached to the branch.

The final touches include adding extra plant down to the inner cup, creating a soft and insulated environment for the eggs. The entire process can take up to 10 days to complete.. Despite the small size of the hummingbird, the resulting nest is a marvel of engineering, typically about the size of a walnut (meaning just about 2 inches across and 1 inch deep!), yet strong enough to protect and nurture the next generation of these tiny birds. The nest, with its elastic properties, expands as the chicks grow, providing a secure home until they are ready to fledge.

Finding a Hummingbird Nest

Because they are so tiny and well camouflaged, a Ruby-throat’s nest is usually very difficult to spot. But you may know that nest building is underway nearby if you see a female hovering around the eaves of your home collecting spider webs. In addition to planting native pollinators and providing a nectar feeder, another way to attract hummingbirds to your yard is to leave spider webs undisturbed so they are available for hummingbird nests! And remember, if you are lucky enough to find a nest, it is illegal to disturb or damage it, so leave it be. Even after nesting season is over, it is best to leave the nest alone and admire it without touching it. 

Conclusion

The nest-building process of the Ruby-throated Hummingbird is a testament to the ingenuity and resilience of nature. Each nest is a unique creation, perfectly adapted to its environment and crafted with a blend of skill and instinct. Through her diligent work, the female hummingbird ensures the safety and comfort of her offspring, contributing to the continuation of her species in a world full of challenges. If you ever spot a tiny, camouflaged nest high in the trees, take a moment to appreciate the remarkable effort and craftsmanship that went into its creation.

Two videos of Ruby-throats building their nests:

From the Michigan Nature Association

From the Arkansas Natural Heritage Commission



The (Humming) Birds and the Bees

i Apr 30, 2024 No Comments by

By Brittany Richards

Pollen – so much pollen – is not the only thing wafting on the breeze these days. Love is also in the air! Signs of nature’s fecundity are all around us this time of year. For all of us backyard birders, we delight to see the mating pairs of so many of our songbirds succumbing to the call of the season; the males wooing their mates with fancy feathers and fanciful flights. We know in a few weeks’ time we will see the fruits of their efforts when our feeders are visited by the first fledglings, feathers still fluffy, wings still wobbly. So what about Ruby-throated romance? How do our hummingbirds court and couple?

The Ruby-throated Hummingbird courtship story is a brief affair, more fling than lasting love. It begins when the migrating males arrive first in the summer breeding grounds and stake a claim. They will look for abundant food sources and then aggressively defend an area of up to a quarter acre. Tiny but feisty, males jealously guard both food and females within their boundaries. While these fights are typically more about intimidation than injury, with flaring feathers, harsh chirps, and darting dives, there may be occasional casualties. If you find an injured bird, it is best to confine it in a small container, like a shoebox, lined with a towel, and take it to a nearby wildlife rehabilitator. (On the Wake Audubon “Links” page you can find a list of local organizations under “Injured birds and other wildlife”.) 

Threat Display. Photo by Mike Dunn.

Threat Display. Photo by Mike Dunn.

Food is such a precious resource for hummingbirds who need to feed so frequently that females will also guard food sources such as nectar feeders. To encourage fewer squirmishes, you can plant flowers to offer more feeding locations in your yard, or put out multiple feeders. The Cornell Lab of Ornithology offers this advice: “Overall, you’ll feed far more hummingbirds by setting out four tiny one-port feeders than one giant eight-port one. Spread them out and the birds won’t have to see one another, arousing their territoriality.”

But back to our love story! After a male has successfully claimed a territory, he will attempt to mate with as many females as possible. When a potential mate is within his range, he will try to get her attention with a courtship display that includes whirring and chirping, flashing the feathers of his gorget (that beautiful ruby throat of his name), and a signature U-shaped flight with dramatic dives from as high as 50 feet above her. When she is perched, he will make short flights buzzing back and forth in front of her. Like many facets of this solitary and somewhat secretive bird’s life cycle, it is not precisely known which aspects of this behavior are most persuasive to females. The flashiness of his throat? The energeticness of his display? But some studies of hummingbirds suggest it is the quality of his territory more than his physical attributes that is most attractive. 

Male with gorget on full display. Photo by Bob Oberfelder

Male with gorget on full display. Photo by Bob Oberfelder

When a male has successfully won the affection of the female, the act of mating lasts only a few seconds. As with most birds, this involves a “cloacal kiss” where the cloacae (the single rear opening that is used for digestive, urinary, and reproductive purposes) are briefly pressed together. And this is where the romance ends! Unlike the doting males of some species, who may build the nest or feed their partner or help rear the young, Ruby-throated males will part ways as soon as mating is complete, leaving the female to perform all the duties of raising the young on her own. But while she may be a single parent, she may still receive some indirect support from the male. There is some debate whether females will build their nests precisely in the territory of their mating partner, or a neighboring territory of her own. But it is believed that she and her young will benefit from the male’s territorial guarding in her vicinity because she and her young will have less competition for nearby food sources. 

Ruby-throats are definitively polygynous, meaning the males will mate with multiple females in a season. But it is also believed that they are polygynandrous, meaning the females will mate with multiple males as well. A female will have one to two broods a year, with a single brood more common in the northern part of the breeding range where the season is shorter, and a third brood being possible in the southernmost part of the range where the season is longest. Here in North Carolina, a female will typically have two broods, almost always of two eggs each. 

With spring fully sprung, and the season of romance in full swing, hopefully your backyard is aflutter with love birds of all sorts. Meaning in a few weeks time, you’ll be treated to some adorable baby sightings as well! 

A male’s ruffled ruby throat. Photo by Bob Oberfelder.

A male’s ruffled ruby throat. Photo by Bob Oberfelder.

 



The Rubies Return

i Mar 31, 2024 No Comments by

By Brittany Richards

The pear and cherry trees have bloomed and leafed out. The eastern redbuds are glorious fuschia. Your yard is abuzz with chubby carpenter bees and flying insects of all sorts. But how do you know it’s really spring? The first hummingbird sighting of the season, of course! Our bird of the year, the Ruby-throated Hummingbird, will be returning soon (if you aren’t already one of the lucky few to have welcomed an early visitor). While there is still much unknown about the exact mechanics of their spring migration, what scientists have been able to learn offers a fascinating glimpse at the remarkable feat these tiny birds undertake on their way to our backyards. 

Ruby-throat in flight. Photos by Mike Dunn

We know from our last blog post that our hummingbirds are preparing for their spring journey by fattening up in their wintering grounds and refreshing their beautiful plumage, and that male birds will leave first to establish their territory. Just as they did last fall, most birds will take an overwater route and fly 500 miles nonstop over the Gulf of Mexico before reaching the Gulf coast states to refuel while making their way to the North Carolina piedmont and beyond (and smaller numbers will hug the coast to migrate over land). It is believed that their overwater flight largely takes place at night, while their migration over land happens during the day and near ground level to take advantage of food sources for frequent feeding. 

But why do they leave their tropical paradise at all? Ruby-throated Hummingbirds evolved to take advantage of the seasonally available flowers in their two habitats, and that adaptation is now a hardwired instinct. Their northern summer breeding territory is six times larger than their winter territory (25 million square miles versus four million square miles), so when nectar-producing flowers bloom in abundance across eastern North America, hummingbirds migrate to feast on the bounty. They likely know when it is time to migrate because they are sensitive to changes in the photoperiod, or the amount of daylight hours in a 24-hour timeframe. So as spring days grow longer, hormonal signals trigger the instinct to head back north. 

Ruby-throat at Jewelweed flower. Photo by Mike Dunn.

When the Ruby-throats reach the southeastern United States, they will fan out across the summer range, as far west as Texas and as far north as Canada. Studies of banded Ruby-throats shows that birds will take astoundingly consistent routes: flying the same route in spring and fall and the same route each year, and even stopping over at the same places along the way, and in some cases stopping on the same day, until they return to their own birthplace where they hatched. So the birds you see return to your feeder are indeed likely the same birds you saw last year. With an average lifespan of three to four years, you can enjoy seeing the same birds for several summers. Scientists do not know precisely how they accomplish this amazing precision, especially considering Ruby-throats migrate alone without a parent or flock to guide them. Along with instinct, they may use some combination of sensing the Earth’s magnetic field, using the sun as a compass, and noticing landmarks to remember their favorite layovers and find their final destination. 

As we all anxiously await a familiar fluttering at our feeders, the National Audubon Society has a handy list of hummingbird feeder FAQ to help us prepare a tasty meal for our hungry migrants. Some general tips to keep in mind:

  • Not only is red-dyed nectar unnecessary, it’s actually harmful. A simple homemade recipe is one part white sugar to four parts water (and never honey, molasses, brown sugar, or artificial sweeteners). 
  • The hotter the weather, the more frequently the feeder needs to be cleaned. Placing your feeder in the shade is a good way to keep it from spoiling as quickly. Early in the season you also won’t need as much, so you can use less (and waste less!) at the start. 
  • In addition to your nectar feeder, native plants are a great way to attract and feed hummingbirds (and other pollinators). The National Audubon Society also provides tips for creating a hummingbird-friendly yard and a database of native plants based on your zipcode. 

Ruby-throat at feeder. Photo by Bob Oberfelder

Hopefully you’ll mark the true start of your spring season with a Ruby-throated visitor or two very soon. After their long journey north, your birds will be very grateful for your nourishing nectar! 

Embracing the Majesty of the Northern Cardinal

i Mar 26, 2024 No Comments by

Authored by Rick LaRose

This is the first of a series of blog posts to spotlight some of our native songbirds matched to the colors of the rainbow Pride flag, starting with the color red. Find more context here.

The Northern Cardinal, with its vibrant plumage and enchanting melodies, is a beloved symbol of beauty and vitality in North Carolina. Let’s delve into the captivating features and behaviors of this iconic bird, which graces our landscapes with its presence year-round.

Size and shape

– Cardinals are medium-sized songbirds, measuring around 8 to 9 inches in length.

– They have a distinctive crest on their heads and a sturdy, cone-shaped bill, perfect for cracking seeds.

Color and pattern

– Adult males are adorned with brilliant red plumage on their bodies, crest, and face, contrasting with their black masks and throat patches.

Northern Cardinal, male. Photo by Keith Kennedy.

Northern Cardinal, male. Photo by Keith Kennedy.

– Females are predominantly brown with red tinges on their wings, tails, and crests, while juveniles have a similar appearance to females but with a duller coloration.

Northern Cardinal, female. Photo by Keith Kennedy.

Northern Cardinal, female. Photo by Keith Kennedy.

Calls and songs

– The Northern Cardinal’s song is a series of clear, whistled phrases, often described as “birdie, birdie, birdie” or “cheer, cheer, cheer” which to me can sound like a rapid-fire ray gun.

– They also produce a variety of other vocalizations, including sharp chips and metallic chinks, used for communication with mates and warning of predators.

Habitat

– Cardinals are adaptable birds, found in a variety of habitats including woodlands, shrubby areas, parks, and suburban gardens.

– They prefer areas with dense vegetation for nesting and perching, as well as access to open spaces for foraging.

Behavior

– Northern Cardinals are primarily seed-eaters, feeding on a variety of seeds, grains, and fruits, as well as insects and spiders.

– They are often seen foraging on the ground or in low vegetation, using their strong bills to crack open seeds and extract the nutritious contents.

Migration and seasons in NC

– Cardinals are non-migratory birds, maintaining their territories year-round, and often remain paired with the same mate for several breeding seasons.

– They are most active during the breeding season in spring and early summer, when males sing to establish and defend their territories.

– Cardinals may also be more visible during the fall and winter months when food sources are scarce, often visiting backyard feeders for supplementary food.

Meaning

– In many cultures, the Northern Cardinal is associated with positive attributes such as vitality, renewal, and strength.

– Its vibrant red plumage is often seen as a symbol of energy, passion, and courage, while its melodious songs are thought to bring joy and happiness.

– Some believe that spotting a Northern Cardinal can bring good luck or serve as a reminder of loved ones who have passed away. For one of my cherished friends, they’re a symbol that her departed mother is near.

The Northern Cardinal is a revered emblem of North Carolina’s natural beauty, captivating us with its striking appearance and captivating melodies, providing color and song to our landscapes throughout the year. No wonder the NC General Assembly of 1943 named this unmistakable red, crested songbird as the official State Bird of North Carolina.

A common site in North Carolina, providing color and song to our landscapes throughout the year, the Cardinal is often credited as “the red bird” that first piques the interest of backyard birders. I find them to be the first birds at my feeders in the morning, and the last to visit at dusk. Have you seen the same?

So, let’s celebrate the Northern Cardinal for vibrantly representing the color red of our rainbow flag and captivating us with their beauty and symbolism.

Sources:

National Audubon Society (Guide to North American Birds | Audubon)

Cornell Lab of Ornithology (All About Birds)

Birdzilla (Bird Meaning & Symbolism)

And my own personal experiences

======================

Highlighting a Colorful Array of Birds and the Catalyst for It: Inclusivity

i Mar 20, 2024 No Comments by

Hi all, Wake Audubon board member and Equity, Diversity, Inclusion and Belonging (EDIB) co-chair Rick LaRose (he/him) here.

Starting this month, you’ll begin to see posts to our blog about birds other than our bird of the year, which as you know by now is the glorious ruby-throated hummingbird. Here’s just a quick note to invite you to read those posts, and provide an explanation as to what they’re all about.

Last fall Wake Audubon partnered with local nonprofit Field Inclusive, Inc. to co-create and pilot a Beginning Birders Program that’s tailored for historically excluded and underrepresented groups, communities and organizations to build skill and confidence in their enjoyment of the outdoors. The LGBT Center of Raleigh, Outdoor Afro, City of Raleigh Parks and the NC Wildlife Resources Commission are partners with us too. Segments of our program speak to field and social safety concerns by those marginalized by others. I’m proud to say that our pilot workshops with members of the BIPOC and LGBTQ+ communities were well received.

For those of you new to Field Inclusive, Inc. nonprofit, it was spearheaded by two amazingly impressive women at NC State University, Lauren Pharr and Murry Burgess. Learn more about them and Field Inclusive on their website.

Wake Audubon proudly sponsors Field Inclusive research and climate change grants, and champions their mission to amplify and support marginalized and historically excluded field biologists. Field Inclusive envisions a world in which the outdoors feels safe and welcoming regardless of personal identity. And so do we.

Wake Audubon pledges to advance our mission with EDIB at the center, and provide activities where all can safely access and celebrate nature as their authentic selves. Read more in our statement on EDIB.

This year Wake Audubon and Field Inclusive will excitedly continue to co-host programming for BIPOC and LGBTQ+ participants, as we also gear up to create offerings for Persons with Disabilities. We celebrate these efforts towards an inclusive outdoors.

Why be inclusive?

From a human perspective, every one of us is unique. What opportunity that poses for all of us. I’m constantly awestruck by all I learn, and the perspective and inspiration I gain from opening my heart and mind to receive the lived experiences of others. To be quick to pass judgement denies oneself of such riches.

From a conservation perspective, it takes the world to save the planet. Just as birds differ in color, size, behavior, geographical preference, and countless other ways, so is there equally remarkable diversity of the human species.

Protecting and conserving nature and the environment transcends political, cultural, and social boundaries. Respect, inclusion, and opportunity for people of all backgrounds, lifestyles, and perspectives will attract the best ideas and harness the greatest passion to shape a healthier, more vibrant future for all species who share our planet.

Now, back to those bird posts. As a way to promote a birding mindset, the executive director of the LGBT Center of Raleigh, Kori Hennessey, and I thought it would be fun to spotlight a few species of birds, and to correlate each to a color of the rainbow Pride flag. So, starting next week with the color red, I’ll familiarize you with a bird a month. This may provide new knowledge to the novice birders among you, with perhaps a nugget or two new for you seasoned birders too.

Thank you for supporting Wake Audubon in our mission to advocate nature and environmental conservation, and to lead education, conservation and advocacy efforts to grow our region responsibly and with concern for birds, wildlife and the places all of us live together.

——–

Welcome to the month of spring!

i Feb 29, 2024 No Comments by

Authored by John A. Gerwin

As I write this, in late February, there are many trees in flower, along with the usual spate of Daffodils and a few other early herb arrivals.  Speaking of early, I watched a pair of Carolina wrens gathering large clumps of moss, and begin constructing a nest in a shrub in the backyard, on February 21. It seemed amazingly early.  Soon, we will be seeing additional “early birds”.

Normally, we expect to see the first returning Purple Martins to Wake County in early March. That said, our colleague Courtney Rousseau recently reported one from Holly Springs, on February 24. Things are happening earlier and earlier.  Considering history, we expect to get a few reports of Ruby-throated hummingbirds in North Carolina in late March. However, most of us in Wake County are accustomed to seeing our first of the year hummers in the first two weeks of April.  You can follow along at this website: https://maps.journeynorth.org/map/?map=hummingbird-ruby-throated-first&year=2024

In most migratory bird species, males move through or arrive to a territory prior to the females. This makes sense in that males are racing to get back, get a prime piece of habitat, and establish a territory. Ruby-throats are similar in this regard.

In order to return to its breeding area, a given hummingbird will once again fatten up, the way it did when it was getting ready to head south. An individual that is not in migratory status or condition will weigh 3-4 grams. By the time it is ready to migrate it may weigh 6g. Note that in some cases, the bird has doubled its weight!

So, for most Ruby-throats, March is a month of gluttony as it were – they are still on the non-breeding grounds in a Mexican or a Central American locality. Many are also completing the body molt. Studies show that the head and throat (gorget) feathers will finish growing in by around mid-March.

Indeed, when you see your first males, try to assess the lower edge of the red gorget. A bird hatched in the previous year will often show a somewhat jagged edge whereas the older birds (greater than 1 year old) exhibit a more concise, straight-edge. It’s now always easy to tell with binoculars, but it can be with a digital photograph. That red gorget by the way will look black at certain angles and the way the light is hitting – but the edges are still edges.

Note that across the species broad range, we see quite a bit of variation from year to year in terms of “first seen” dates, and numbers visiting feeders. This is how nature is – there are various factors that affect the timing of movements of birds, and their subsequent distribution. And we don’t understand all of these factors.

As we are seeing more and more, plants are springing forth sooner in the season. Some birds are beginning to nest earlier than ever before. One way we discern these patterns is through the contributions of many amateur naturalists. So if you are so inclined, be sure to post your observations to your favorite website  – which may be eBird, or Journey North, or iNaturalist.  Here’s the map from 2023 for Ruby-throat observations submitted to Journey North. You can use the slider to see how things look by the week.

https://maps.journeynorth.org/map/?map=hummingbird-ruby-throated-first&year=2023

And now that you know some hummers may show up as early as late March, you can plan to have your hummingbird feeders ready to go.  In the early spring, I prefer to start out with very small quantities of my homemade nectar. I know that visits to my feeders, in early April, we will few and far between. If I put out a feeder full of nectar, it usually gets moldy long before it is consumed. So I wait and see how many hummers seem to be around before I put out a larger quantity.

And remember – these little tykes consume many small arthropods. Indeed these make up about 50% of their diet.

Attached are some pictures to get your ready. I realize this only makes the month of March feel that much longer….. but this year we have Easter Weekend to help with the waiting….. maybe your Good Friday will be super good when you spot your first Ruby-throated Hummingbird of 2024.

Photo legends:

All photos by Bob Oberfelder

#1: Here is a “classic” view with full light hitting the gorget of a male Ruby-throat.

#2: This male might be a younger male – the edge of the gorget is slightly jagged. Note the darker area of the throat due to the angle of light, which in this case is not refracting to allow the red wavelengths.

#3: The color on the gorget of this individual appears a bit duller. The color is derived from the interaction of light waves and the feather structures and the way they overlap. Small changes in the structures (wear) or overlapping (puffed up or not)  can yield slightly different hues to the red.

#4: A classic “I think I have discovered a new species of hummingbird!”.  I have received many such emails and phone calls. Many folks do not realize that the gorget color is the result of structural features of the throat feathers, and not pigments. If the light does not hit and/or refract back in a Goldilocks manner (“just right”), the color appears dark, or black, as in this individual.

Ruby-throated Hummingbird – February

i Feb 1, 2024 No Comments by

Author: John A. Gerwin

February is a chilly, darker month. In the Piedmont of North Carolina, we experience some of the coldest nights, and least amount of daylight. The Ruby-throat is a Neotropical migrant, similar to the warblers, vireos, thrushes, tanagers and more that breed in NC. Most of “our” hummingbirds departed months ago. In NC, some leave as early as late July, others follow as summer turns to fall, and most are gone by late October. They make their way to Mexico or countries in Central America.

Ruby-throated Hummingbird, back view with tail spread. Photo by Mike Dunn.

Ruby-throated Hummingbird, female. Photo by Mike Dunn

Most Ruby-throats migrate south. However, not all of them do. For years, folks have reported wintering hummers in NC. And for some of those years, Susan Campbell and colleagues have caught, measured, photographed, tagged, and released many. They have found a mix of species, but many were Ruby-throats. We do not know why this happens (but we have some opinions all the same. We’ll see if we can get Susan to chime in one month).

During the winter months in Mexico/Central America, a Ruby-throat will be in places with a handful of other species. Keepers of bird lists currently list 340+ species of hummingbirds – all in the western hemisphere.  “Neotropics” means New World Tropics.  I’ve seen a few Ruby-throats on the west side of Nicaragua for example. Where the Ruby-throat can be found in Nicaragua, one might also find two dozen other species of hummingbirds. I have included pictures of a few of these other species.

In the non-breeding season, the Ruby-throat prefers habitat in areas that are drier overall, and often a bit scrubby (forest openings with second growth, forest edges, and some agricultural settings; among others). They will nectar at flowers we might grow in our gardens – various Salvia species for example. They continue to feed on minute arthropods for protein, and have an inordinate fondness for small spiders.

We know that hummingbirds exhibit some extreme life history behaviors and physiological adaptations. One of these concerns the molt cycle and there are aspects of the molt cycle we do not yet fully understand. Hummingbirds, as a group, rely on flight for feeding. Due to their small size, they are subject to extreme “stress” in order to maintain their high body temperature and functions. All to say, they do not molt quite like other birds. I can’t get into all the details here but will note that adults undergo a complete molt (body and flight feathers) after the breeding season. What’s really curious is that recent research has shown that some individuals undergo a molt in summer and apparently another during the winter.

In songbirds the post-breeding season molt can be completed in 6-8 weeks. In Ruby-throats, it is reported to be slower and much more protracted, when compared to the migrant warbler or thrush.. An interesting aside: in 1936 a researcher counted the number of body feathers on some Ruby-throats; he came up with 940.

At the species level then (Ruby-throat), the molt cycle runs from late summer to mid-winter. Individuals will do things differently, and as mentioned some may begin to molt body feathers in late July. These Ruby-throats then migrate while they are molting (or, if you prefer, molt while they are migrating). The question is, when does that July-molting bird complete the molt? No one knows for sure. One researcher did a fairly thorough study of the molt of Ruby-throats, assessing individuals in Mexico and Central America. His data showed that many Ruby-throats began a molt of the flight (wing/tail) feathers in November and completed it by the end of February. Many (most?) individual Ruby-throats complete the body molt in March, when the males’ new gorget feathers grow in.  Still, other aspects of the molt remain unknown. To understand precisely which birds are molting what/when/where, we will need a lot of marked birds that can be followed, month to month.

In February, Ruby-throats are sharing time/space with a large variety of tropical hummingbird species. In addition, they are preparing for the northward migration and some will indeed begin to migrate north during February. Many aspects of their migration also  remain unknown – but we do know that some will arrive in the southern U.S. by early March.

Here we provide a link to Cornell’s eBird website for the non-breeding range of the Ruby-throated Hummingbird. This is a page where the user can zoom in and do other ‘animations’ (note also options on the right-hand side).

https://science.ebird.org/en/status-and-trends/species/rthhum/range-map?season=nonbreeding

Finally, I have included photos a few species of tropical hummingbirds in Nicaragua, which ranges overlap that of a given non-breeding Ruby-throated Hummingbird.

Crowned Woodnymph – male

Crowned Woodnymph – female

Long-tailed Hermit

Rufous-tailed Hummingbird

Ruby-throated Hummingbird – 2024 Bird of the Year

i Dec 30, 2023 No Comments by

Authored by Brittany Richards.  Goodbye. Hello! While this tiniest of feeder visitors may have bid backyards farewell months ago, Wake Audubon Society warmly welcomes as its 2024 Bird of the Year, Archilochus colubris: the Ruby-throated Hummingbird!

Even as the days grew shorter and pumpkins began appearing on porches, you replenished your nectar, just in case the emerald-backed and ruby-throated birds that enchanted you all summer needed a final sip of fuel before they began their long journey south. But as the maples and sweetgums turned crimson and gold, you realized your feeders had fallen silent, and you resigned yourself to the fact that even the last stragglers of the season had moved on, and you will have to await the ruby-throateds’ return in the spring. 

But where will the birds who nipped nectar all summer in your yard spend their winter? As improbable as it may seem, these birds, with an average weight of just about 1/10 of an ounce – less than the weight of a single nickel – will travel thousands of miles to reach their wintering grounds in Central America (extending from southern Mexico, throughout the Yucatán Peninsula, to as far south as Panama). A smaller population of birds will stay along the tip of Florida and the southern Atlantic and Gulf coasts of the US to spend their winters stateside. So when our North Carolina days have become chilly and our flowers have all but disappeared for the season, the birds who flitted and fed around your yard all summer may be as far as 3,000 miles away enjoying a verdant, tropical winter.

Surprisingly little is known about the exact routes and duration of their migration, but research suggests that birds stopover throughout the Gulf coast, feeding and refueling for only a few days at most before continuing their journey to their final destination. It is believed that birds follow both an overland route, but also an overwater route that requires an 18-22 hour nonstop flight of 500 miles over the Gulf of Mexico. Just as amazingly, all ruby-throated hummingbirds make this trek alone, even first year migrants, who navigate on instinct alone without a parent to guide them. One study of ruby-throated hummingbirds showed that the southernmost birds of the summer range migrate first. So with our hummingbirds in North Carolina generally departing in late summer, those October feeder visitors very well may be birds from further north just passing through on their way south. 

Though it was once feared that leaving feeders out too late in the fall would discourage hummingbirds from migrating, it is now known that this is a myth. It seems a combination of hormonal signals, the availability of natural food sources, and the decreasing amount of daylight triggers the migration instinct. So while it is certainly reasonable to store your feeder when it has been two weeks since your last sighting of a hummingbird, it will do no harm to leave it out longer. And in fact, should you decide to provide nectar all winter, you might even spot a visit from a so-called winter vagrant. Ruby-throated Hummingbirds are the only species with a breeding range in the eastern United States, but with increasing frequency, species either beyond their typical range or birds overwintering between October 15 and March 15 can be spotted in North Carolina. In particular, eastern sightings of the western species, the Rufous Hummingbird, which usually winters in Mexico, are being seen at feeders in the southeast US. It is unknown if more birds are actually spending their winters outside their usual wintering grounds, or if more people are just monitoring their feeders throughout the winter and reporting these sightings. If you do spot a winter visitor, the North Carolina Museum of Natural Sciences has an ongoing project to track these vagrants, and you can report your own sighting on their website

Most of us may not enjoy this jewel-toned wonder again until the coming spring, but Wake Audubon Society looks forward to celebrating and exploring the beautiful and fascinating ruby-throated hummingbird all year! 



Adieu to Our 2023 Bird of the Year – the American Goldfinch

i Nov 30, 2023 No Comments by

The American Goldfinch Wake Audubon’s 2023 Bird of the Year!  by Phil Doerr

It’s time to bid this year’s star adieu and turn our attention to a new rising star coming in January when a new bird ascends! But for now, our American Goldfinch will be with us all winter. They will of course be a bit less obvious, as the fall molt to much duller colors is  happening before our very eyes, so watch carefully! And don’t forget  to keep track of these wonderful birds when they visit bird feeders in your neighborhood, or look for them along roadside ditches, and old fields. They’ll still be there, dangling upside down from sweet gum balls, or dried goldenrod flowerheads .

During the year we explored some fascinating  features of the biology of this stunning and remarkable bird. We saw that Goldfinches are able to thwart would be brood parasitism by brown-headed cowbirds simply because they are vegetarian, and cowbird chicks starve without animal protein and fat. We also saw that some clever females hedge their genetic bets by choosing to raise a second brood after the first has fledged into the care of her mate. The second brood is with a different male, so if successful, the female produces a large number of offspring, with a diversity of genetic traits, increasing their survival probabilities and spreading her genotype more broadly. And at the end of the day, that’s what evolution is all about! Whoever leaves more offspring, more widely distributed wins!

We also saw that our local goldfinches are largely non-migratory, but that in winter our region often hosts short distance goldfinch migrants from colder climate areas to our north where goldfinches nest. Consequently, our local goldfinch populations do swell in winter, and they become quite common. And while goldfinches are indeed common throughout  the southeast, the forecast for habitat changes with the current rate of warming associated with climate change, the future for goldfinches in North Carolina is tenuous. North Carolina east of the mountains will become too hot and dry for goldfinches to nest successfully. Goldfinches will shift breeding ranges northward unless we cease pumping fossil fuel residues into the atmosphere, and we will no longer be witness to the stunning gold of the breeding males!

What can we do for American goldfinches, to ensure our grandchildren will see breeding plumage birds? We can advocate for government policies to eliminate fossil fuel burning and promote the conversion of our entire economy to renewable energy. Failure is not an acceptable option, because it’s not just American Goldfinches we’ll lose, its life, and business as we know it. Let’s get to it!

To demonstrate that we can successfully address big environmental challenges, I want to call attention to an anniversary!

2023 is the  50th Anniversary of the Endangered Species Act!  This monumental bipartisan act of Congress was signed into law by president Richard Nixon, and over the years has been the linchpin contributing to the recovery and delisting of the Bald Eagle, the Peregrine Falcon, the Brown Pelican, the American Alligator, and the Channel Island Fox. In addition, many other species are on the path to recovery with growing numbers because of the protection and positive conservation actions under the ESA. These include Green Sea Turtles, Humpback whales (some populations delisted), Whooping Cranes, Piping Plover, and California Condors among others.  Its an anniversary worth celebrating!

And another success!

We also addressed the threat of the ozone hole in our upper atmosphere! When in the 1980s coolants escaping from refrigeration units and chlorine based propellants from spray cans were discovered depleting the ozone layer humans were at increasing risk from UVB ray induced skin cancers. The ozone layer absorbs UVB and reduces it’s incidence at the earth’s surface, reducing the cancer risk. An international treaty banning these substances facilitated by the United Nations (1989) has resulted in steady recovery of the ozone layer which is on track to full restoration by 2045.

The point is we (the world!) can accomplish big things. Yes, we can! Yes we must!

Have a great holiday season, and new year, and thanks for all the hard work you do for the for the planet!

Phil Doerr, Retiring Wake Audubon Board Member

[email protected]

Migration, Local Movements, and Residential Habitats

i Oct 31, 2023 No Comments by

Authored by Phil Doerr

November! It’s midway past the time of year when fall migration is really exciting! Every day (well actually night-time!!) holds the promise of delivering  another delightful arrival of amazing numbers of birds, and the potential for some of our favorite woodlands to host a new group of warblers and thrushes. We closely monitor the fruiting dogwoods, tupelos, hackberries and persimmons or oaks for activity.  Almost any oak species supports bocoos of the wee invertebrates sought by the famished hordes! October 7, 2023 “Birdcast.info” radar reported 1.2 billion birds were in flight across North America and Wake County recorded passage of more than a million birds that same night! Most of these birds are passing through to Central or South America, but recently we’re seeing the arrival from the north of a number of species of sparrows that will spend the winter with us and brighten our outings at least until April next year! The list includes Song, Chipping, Savannah, White-throated, Swamp, Field, Vesper, and occasionally White crowned sparrows. The brushy areas these birds frequent are often shared with American Goldfinches, our locally nesting birds, most of whom stay with us all year. However, our winter visitors from the north include some goldfinches fleeing northern regions where the cold is more intense. Consequently, American Goldfinches are often considered to be short distance migrants, or largely non-migratory in the south. Collectively there’s a moderate southerly shift to the continental goldfinch population.

November Goldfinch photo by Bob Oberfelder.

November Goldfinch photo by Bob Oberfelder.

Above photograph is of a post breeding season, likely male, goldfinch w/buffy wing bars, yellow shoulders and throat with a rich almost rusty back. Some of these have been around us recently, this one was “captured” by Bob Oberfelder. Most goldfinches will seem a bit dull soon as they acquire winter plumage via the fall molt.

For the long distance migrants we’re by now all aware of the extreme dangers the night fliers face from glass towers and artificial lights, especially during heavy migration flights. To prevent thousands of  bird deaths on such nights we turn the lights off from 11pm to 6am. It’s very simple and easy! But what about our more local bird movements? Is there danger here?

If we are indeed making our yards bird friendly, with native plants, replacing all or part of the ecological deserts represented by the “lawn” then it’s important we make our yards bird SAFE!

Lights, and glass in neighborhood parks and nearby residences with good habitat can be a death trap for migrating birds and even our winter residents or visitors. Lights may confuse birds and while the habitat may seem otherwise suitable, even single-story structures with windows will reflect habitat and kill birds.

Recent research from Oklahoma State University biologists that examined how bird population abundance reflected mortality revealed that some species were disproportionately vulnerable. These included Black-throated Blue Warbler, Ovenbird, Ruby-throated Hummingbird, Yellow-bellied Sapsucker, Wood Thrush, Gray Catbird, Common Yellowthroat, Brown Thrasher, White-breasted Nuthatch, and American Goldfinch. Of special concern to us is that the first several birds in that list are long distance migrants, but there’s continuum to the last three species (including our BOTY!) that are largely short distance migrants or even non-migratory. The long-distance migrants often travel at night in large flocks and are especially vulnerable to the lighted  glass expanses in large cities. The non-migratory birds, (read goldfinches!) seem more vulnerable to local hazards where they live, and thus residential and business structures may be a frequent problem. This underscores the need to eliminate or reduce lighting in or near our homes, and to use bird safe glass so that our feeder citizens (nuthatches, goldfinches, titmice and chickadees) are less vulnerable to window strikes.

For this end of fall migration season month please:

1)Turn out the Lights 11pm-6am!

2) Leave your leaves (the creeply crawlies need’em) and

3) Leave last year’s flowering stems as well-at least until spring greenup. is starts! (there’s lots of eggs and overwintering bugs in there.

 As always thanks for all ya’ll do for the birds-keep it going!

Phil Doerr,  Wake Audubon Board Member & Volunteer

To see all of the posts on the American Goldfinch, go the our Bird of the Year site