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!!
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.
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])