Authored by Phil Doerr.
June, and the distractions of our exciting and often very colorful spring migrants arriving and passing by in waves overnight is mostly over, so now we can concentrate on our nesting or soon to be nesting locals. “Birdcast.info” has completed the spring 2023 run with, often stunning, nightly radar displays of the millions of birds that pass over us on their way to northern nesting habitats. Not to be outdone, our Bird of the Year (BOTY) the American Goldfinch is arguably the most colorful of our local breeding birds. (Northern Cardinals may beg to differ!)
American Goldfinch male, breeding plumage. Photo by Bob Oberfelder
With summer truly here, American Goldfinches are now focused on nesting and the number of courtship chases we began to observe in May is increasing. Pairs are getting serious about locating nest sites, and females will soon begin nest construction, requiring 6-7 days. They’ll look for dense shrubby thickets, and wooded edges in which to work their magic of twig placement and weaving of spiderweb into a sturdy yet soft but strong cup lined with some of the same downy material collected from thistles and milkweeds. Another few days for egg laying follows with about 2 weeks of incubation before synchronous hatching takes place. Then it’s all high intensity seed collection to stuff the always open mouths demanding to be filled with thistle and other seeds. After 2 weeks as nestling the youngsters “fledge” (leave the nest). They remain in the care of dear old dad another few days while they perfect flying abilities and learn how to locate seeds! With fledging, Mom, sometimes moves on to another partner and another nesting cycle which increases her annual and lifetime productivity, and that in part compensates for the fact goldfinch females are out-numbered by males in the population.
Goldfinches are among the latest nesting of our locals, because they are almost exclusively seed eaters, and hold off the energy sapping breeding effort until summer, when native annual and perennial plants are mature, producing lots of nutritious seeds. Goldfinch beaks and their acrobatic ability to dangle on vegetation render them especially adapted to extracting thistle, teasel and other small seeds from mature seed heads. Native asters and sunflowers are seed favorites as well.
To help American Goldfinches we are reminded of the importance of pollinator gardens with native asters, coneflowers, and that we can replace part (or all!) of our lawn with natives! Pollen, seed producing wildflowers, plus native trees (esp. oaks!) make for a healthy wildlife friendly habitat around our homes.
As with many small songbirds, goldfinches are occasionally parasitized by Brown-headed Cowbirds, which leave their eggs in the nests of a “host” species to raise their chicks. The victimized birds don’t seem to recognize the intrusion and feed cowbirds chicks rather than their own. Furthermore, host species chicks are typically booted from the nest by cowbird chicks, and they die. Unlike for many parasitized songbirds, however the “just outcome” here favors the goldfinches. Because goldfinches are adapted to bring only seed to their chicks the cowbird chicks which require animal protein in the form of “bugs” and spiders to thrive, soon starve.
During June, Keep an eye for goldfinch behaviors such courtship chases and males singing from conspicuous perches suggesting nesting is imminent.
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May 31 ended our 2023 Lights Out Wake! Campaign, but September will initiate the return south flight beginning for many birds and when we will again need to think about dimming the outdoor lights and encouraging building managers to do the same 11pm-6am ‘til November30!
Thanks for what you do to conserve birds and all wildlife! It is the way…
Phil Doerr, Wake Audubon Board ([email protected])
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])