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Late Summer American Goldfinch behaviors and climate change.

Authored by Phil Doerr

Hopefully some of us are out seeing numbers of recently fledged juvenile American Goldfinches like this hot (panting) youngster Bob Oberfelder “captured” for us recently!

American Goldfinch baby, Cary, NC

Post nesting, Goldfinches of all ages tend to spread out across local landscapes with early to mid-successional vegetation, supporting lots of seed producing “weedy” species! Goldfinches will soon begin to aggregate in small foraging groups and make the rounds of suitable seed patches. In a few weeks they will begin the fall molt to winter (duller) plumage and begin to all look alike! In our part of the world, goldfinches are a bit nomadic, but definitely not really migratory. Birds nesting much to the north do migrate to our area or even much farther south for the winter. The need for seeds in our increasingly dormant pollinator gardens, roadsides, and field edges will increase as fall edges into winter.

Will NC lose our 2023 Bird of the Year as a Breeding Bird? Various climate change scenarios predict that in the NC piedmont we may lose our nesting American goldfinches as the environment becomes too hot and dry to support nestling survival. We may only see these delightful creatures as winter residents from the north, absent the spectacular breeding plumage males. Check out “Audubon Guide to North American Birds” on line for American Goldfinches and scroll down to “How Climate Change will reshape the range of…” As we are now on a trajectory to hit a 1.5 degree C global temperature increase, American Goldfinches will most certainly lose 34% of  current breeding range, will only nest in our higher, cooler mountain areas, and if we fail to keep below a 3 degree C increase goldfinches will no longer nest in North Carolina at all, while losing 65% of current U.S. breeding range. The interactive Audubon website allows you to play out the resulting scenarios for each combination. Please explore! You will also see another side of this dramatic change, because while goldfinches lose much suitable breeding range in the US, they gain some suitable habitat to the north, much of it in Canada. Most North American breeding birds are facing similar challenges in the face of looming climate change.

While American Goldfinches may still winter in North Carolina, we may need to travel north to witness the stunning plumage of males in courtship and nesting in the future. Goldfinches do seem likely to fare better than most North American breeding birds, however. Most birds will lose much more habitat than will be gained by the northward march of a warming climate. Audubon report models predict 389 bird species will be at risk of extinction under the 3 degrees C. warming scenario.

And while it’s true that ecosystems are often in flux and ever changing, this current change is not natural! It is the unfortunate result of our callous disregard for the health of the planet and continued dependance on fossil fuels. We are fouling our nest and killing nature in the process.

We’ve just experienced the hottest July ever recorded on earth, while 2023 so far is filled with the one of the largest tallies of catastrophic weather events, ever. Most of these events would have been impossible before global climate warming.

So, what can we do? We must insist that our governments adopt policies for conversion of all energy use to renewable sources and we must be conservation minded in our own use of energy. Period! That’s it!  No more fossil fuels!

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Remember “Lights Out Wake” begins September 10, continuing ‘til November 30, when we will pledge to douse all nonessential lights from 11pm to 6am to save our migratory birds and money! Check out “Birdcast.info” for real time updates on migration!

Thanks for doing all you can for the birds.

Phil Doerr  ([email protected])

Wake Audubon Board

Why Might Some Female Goldfinches Favor Their “First Born”?

Authored by Phil Doerr.  The female goldfinch has by now had over a month of “nesting”, including the demands of nest construction, egg laying, incubation, feeding chicks, and finally perhaps taking a break to fuel up for the fall molt and winter flocking with her “mates”….or she might start all over again with another male, in pursuit of her optional“bet hedging” reproductive strategy. This is the option where she produces a second brood with her genes plus the genes of a second male. Consequently, there are more young and there’s more genetic diversity among those young, all pluses, providing she can pull it off.

Curiously, American goldfinches may utilize  a strategy peculiar to a relatively small number of bird species. This strategy involves invoking asynchronous hatching of the brood. So, one might reasonably ask just what is asynchronous hatching, and why does it happen?

The great majority of birds have evolved the reproductive habit of laying the “usual” number of eggs before the hen (usually!) begins to sit, and incubate the eggs. This continous attentive behavior keeps the eggs warm, and the embyoes growing until hatch time.  And because the incubation of the eggs by the warmth of the hen began simultaneously the eggs all reach developmental maturity simultaneously and hatch at the same time. Why is this synchronous hatching such a commonly evolved reproductive strategy? Certainly it’s a plan that works well for waterfowl or game birds that all need to leave the nest at once and head to the water, or the bush! These chicks are precocial, meaning immediately mobile and able to feed for themselves. It also works well among birds for which nesting season food supplies are reasonably reliable. When the young are suddenly present all at once, the adults are motivated to bring home lotsa groceries to keep all the demanding “gapes” happy. Adults are, in fact, programmed by evolution to keep stuffing food into the always open gullets! This behavior also explains why a tiny common yellowthroat may be observed attempting to satisfy a much larger (and parasitic) brown-headed cowbird chick! And as long as there is always plenty of food, this system works well. Sometimes, however, adults may experience difficulty finding enough food and then all the chicks are likely to die, resulting in a missed breeding season. One might speculate that if an adult bird could “decide” to feed just one or two of the several chicks in the nest, they might survive while the others would die. An unhappy consequence for some, but at least the adults would produce some young that year.

Asynchronous hatching is an alternative strategy that may result when a female begins incubating before all her eggs have been laid…this is a “decision” that may happen by natural selection when variabity occurs. That is, while most females lay all their eggs before initiating incubation, sometimes a female may start to incubate when the second or 3^rd egg is laid.

The outcome is that some embryoes start to develop a few days sooner, and hence hatch a few days before the others. The early hatching chicks get a real jumpstart on their nest mates, often monopolizing food at the expense of smaller mates to the extent they may not survive, and this may be particularly advantageous during a food shortage.

Asynchronous hatching is a strategy that has evolved in a number of raptors and other large birds, as an effective way for relatively long lived birds to produce at least one young in most years. Consequently, many hawks and falcons are among the most familiar groups displaying ansynchronous hatching, given that prey abundance and availability can be notoriously unpredictable. A first hatched, first served, strategy that awards advantage to those first in line!

An important question concerning American Goldfinches is “are there summer seed shortages dramatic enough, or frequent enough to provide a selective advantage?” There’s not much evidence for this, only the fact that because asynchronous hatching does occur regularly, there might an advantage often enough, that the trait persists in the population. Such uncertainty suggests an opportunity for more research to explore asynchrony in goldfinches.

Asynchrony allows some female goldfinches to favor their “first born”, but just why seems an elusive answer!

Thanks for reading, and thanks for all you do for birds. Remember that all those seeds in your “weeds” are important groceries to birds, and to the critters birds eat!  

 Phil Doerr  ([email protected])

Wake Audubon Board

The American Goldfinch Nesting Now!

Authored by Phil Doerr.

Watch for them along woodland edges and shrubby corridors in open fields! It’s July in North Carolina, the heat is building, the milkweed is  flowering, thistles are setting seed and the not always patient American goldfinches are ready! Perhaps worried the male will botch the job, female goldfinches build the nest, using 2-3 vertical stems as a base about which she weaves small twigs and bark strips to fabricate a cup. She’ll then line the cup with small plant rootlets and downy materials from thistle seed or milkweed pods. The females collect the cottony down of thistle seeds and milkweed pods to cushion her eggs. She will collect thousands of these to weave into the  cup of the nest. The entire project is stitched together with spider silk!  And, the resulting cup is famous for being so tightly woven it will hold water. Careful scrutiny of the top down view of the nest illustrates her skill.

This construction may take an exhausting week of work, followed by several days of egg laying, to produce the customary 2-7 egg clutch. Sitting the eggs for 2 a week incubation, the female will take occasional feeding breaks, but is often fed by the male . Once the eggs hatch, the male will begin nearly nonstop seed deliveries for the female to pass to the demanding nestlings. Soon the demands escalate as the chicks grow, however, and both parents will feed. After nearly 2 weeks, the nestlings “fledge” (leave the nest) but continue to beg piteously. The male will feed them a few more days, but the female has more important business, now…. It’s been a month or more since she began building the first nest, and her best investment now is to initiate another brood quickly!

So now she will leave her fledglings with the doting dad to finish the job and often, as we mentioned last month, seeks out another spot to initiate a new nest with another male!

While this may at first seem a questionable behavior it does have ecological, and evolutionary benefits. First, there’s another 6 weeks of summer weather with an abundance of seedy delights and soft fluffy goodies for nest building, so plenty of time to fit another brood in!

Thus the female has a chance to double the number of offspring with her genes in the annual lottery and add the potential benefits of a second male. She’s a bet hedger! No point in putting  your eggs in a single basket when options are available! Second, this strategy also helps to compensate for the unbalanced sex ratio among adults that favors males…it provides an opportunity for  more males to breed than could otherwise. Females are often a scarce resource among American Goldfinch populations. There is some thought that females may be worn out by the fall, and grateful for a less demanding life style.

As always, remember the importance of the weedy edges, gardens and roadside fence vegetation in providing the seed crops American Goldfinches need to survive, and which provide habitat for all the invertebrates (insects, and various creepy crawlies) the other birds need! You can convert  part of your lawn to native plants, and help all the wildlife!

Thanks for all you do for birds!  It is the way!

Spring is full upon American Goldfinches,  2023 Wake Audubon  Bird of the Year!

Authored by Phil Doerr

If you’ve been fortunate enough to have these dainty little seed-eaters frequenting your winter-spring seed and suet feeder offerings you have likely noticed many of them have transformed to a sometimes blindingly brilliant yellow! These bright birds are of course the males adopting their breeding season colors. While the yellow body feathers are emerging

the buffy wing bars of winter have flaked off, leaving the much brighter white wing bars remaining to enhance the yellow/black contrasts. In late April and May you may be seeing birds that look like this at your feeders! Keep your “nockies” and camera handy!!

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Courtship begins in the spring when one or several male birds chase a female. Sometimes several males will chase a female, which allows her to select a mate that demonstrates the best “fitness”, or vigor (=faster, or more aggressive, or??).  The female may take off in an apparently evasive maneuver while the male(s) pursue. During this courtship period, a pair (once a choice is made!) may fly in a circular pattern with the male singing. These behaviors may begin in late spring and continue into June. Again, be sure to keep your “nockies” handy when out and about as you might catch the birds engaged in these aerial antics. Also keep in mind these are very late nesters so pair bonding may still be happening in June with actual nesting usually in July or later! The birds seed diet has them waiting ‘till well into summer, when primary seed producers (especially thistles) have matured and there’s plenty to feed growing youngun’s.

American Goldfinches are typically monogamous but some females change mates after producing their first brood. The female may then leave the nest to begin another brood with a new male while the first mate stays to look after the fledglings. This behavior has evolved in many species to allow females some “bet hedging” that may diversify the genetics of her offspring and increase the likelihood some will have the “the right stuff” to enhance their survival probabilities and ensure her lineage continues. And as it happens most American goldfinch populations have more males than females and this strategy helps balance that evolutionary scale.
To signal that his territory is taken, a male will sing and patrol from perch to perch. He may also cruise around the territory and do a low flight followed by an undulating flight with wings close to his body as he dives down and then spreads them again as he flies upward in several loops. At this time the males are truly spectacular as illustrated by these males Bob Oberfelder “captured” in May 2015, and August 2016 when the wings are almost completely black.

Some Goldfinches will choose to nest in small groups in adjacent shrubs or small trees, a behavior that may reflect good seed sources nearby, and suitable nesting substrate. Predator avoidance may also be enhanced with more eyes present. Again be alert, and if you pinpoint a likely nest area with a male singing, look for additional goldfinches and more nesting.

Also watch for goldfinches that may be working low in weedy areas harvesting thistle down and spider webs to use in nest construction. If you spot this behavior, you may be able to see where a nest is being built.

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Thanks for all your interest in birds! And please consider reducing outdoor light use at night

(11pm-6am) all during May when migration traffic often exceeds 200 million birds in motion every night!

Phil Doerr, Wake Audubon Board  ([email protected])

April Musings on our Bird of the Year

Authored by Phil Doerr

With the “Ides of March” safely behind us, our American Goldfinches have really become just that! Or nearly so! Gold! Lotsa Gold! Recall that our Goldfinches performed a complete molt (replaced all their feathers!) in the fall becoming relatively drab, but males are now, in spring, replacing their body feathers with the brilliant yellow breeding colors! If you’ve been keeping an eye on your feeders, the transition is beginning to show in many males.!

This year, late February to early March was warm enough that daffodils, azaleas, trout lilies, and a whole lot of other spring ephemerals were blooming. We’ve had a really warm, early onset of spring, with a pattern of warm fronts added to general climate warming influences. True to form, March then gave us several cool (cold?) systems that slowed the onset of spring.

The birds do require lots of nutritious seeds to accumulate the energy needed for this transition. In some areas this need may explain the persistence of goldfinches at our seed feeders in spring and early summer. Goldfinches are especially fond of thistle seed. In the wild, and at feeders where during winter “finch years”, they may have to battle with large flock of Pine Siskins for access.  A “finch year” is when large numbers of siskins, purple finches, and evening grosbeaks move south for the winter due to widespread food crop failures in northern forests. .

Now, in addition to noting that some of our winter feeder visitors (eg, purple finches, dark-eyed juncos) are departing to return to northern breeding locations, we’re seeing other changes.

If we’ve been cultivating our native pollinator gardens (maybe even converting portions of our lawns to wildflower meadows?) we might have seen the Goldfinches hanging onto the dried-out seed heads of the coneflowers left from last season.  The important operative here is that we’ve indeed kept all the dried stems of the native wildflowers and “weeds” from last year all through the winter, and until spring “green up”. This undisturbed habitat is crucial to the survival of all our native invertebrates that will feed all the birds and other wildlife that populate our yards and woods. Many of these micro-critters overwinter in hollow stems or the leaf and grass litter in the garden and woodlot edges.

Furthermore, fireflies and native bees overwinter in the litter and first couple inches of ground cover, so it’s important to leave that substrate undisturbed until these critters have emerged, the bees to seek out early blooming plants. Consider leaving your garden cleanup to the very last moment before you cultivate or freshen for the spring. Generally, we should avoid mulching with heavy materials like wood chips, because most invertebrates are unable to burrow in that medium. An undisturbed light natural leaf mulch is best for most native species.

For now, enjoy the goldfinches at your feeders, and watch for migration arrivals and passing birds in your area. Check out https://birdcast.info for migration forecasts and real-time radar tracking of ongoing migration events. Check your yard and nearby wooded areas daily for overnight arrivals. And remember to observe the Lights Out Wake protocols of dousing exterior lighting between  11pm and 6pm so that migrating birds are not confused and crash into buildings or homes.

Thanks for all you do for birds!  For the birds! It is the Way!