With the majority of the summer season already behind us, it’s safe to assume that your local birds have long since laid eggs and raised their young. Over the past few months, many of you have probably come across a bird nest or two, have heard nestlings begging for food or even watched juveniles trying to catch their own meal. But now that late summer is upon us, we can declare an unofficial end to the bird-breeding season. Or can we? Not so fast!
One colorful member of our local band of birds is an exception – the American goldfinch (Carduelis tristis). Goldfinches are our overall latest nesting bird species. So late, in fact, that when most other songbirds are finishing with breeding, goldfinches are just beginning to incubate eggs or feed newly hatched young. And although other species, such as cedar waxwings, are also known to lay eggs rather late in the breeding season, they, as a whole, generally start laying by June. Goldfinches, on the other hand, don’t begin laying their first eggs until the first or second week of July. In New York, goldfinches have been known to lay eggs as late as mid-September!
I suppose the next question is “why such a delay”? The cause of this is not well understood; the late timing may be related to the availability of suitable nesting materials and seeds for feeding young. There’s a very close relationship between the flowering of thistles, an important food plant, and the start of nest building. During the breeding season, goldfinches feed primarily on the seeds of plants in the Aster family – predominately thistle. In fact, nesting success depends so heavily upon thistle that their nesting location is almost always near a good supply of the plant. Even the goldfinch's genus, “Carduelis”, comes from the Latin word “carduus” which translates into “eats seeds of thistle”. Since goldfinches rely upon an abundant food source for nesting success, other sources of nourishment - including goldenrod, burdock, sunflower, chicory and insects - are also incorporated into their summer diet.
In addition to the bird’s close tie with the flowering of thistle, the physiological effects of spring molt may also prohibit early nesting. Goldfinches change from winter plumage to breeding plumage by a complete molt of body feathers. No other member of its family undergoes this second molt in the spring; all the other species have just one molt each year in the fall.
Because they nest so late, most pairs have time to produce only one brood in a season. Though, experienced breeders sometimes produce two broods if eggs are laid early and the first brood is successful.
Since goldfinches are so fond of thistle (also known as nyjer or niger seed), you can increase your chances of getting quality photos by placing thistle feeders near your home. Consider hanging the feeders near a tree so the branches can serve as a natural perch. At the same time, you should be thinking about the proximity of the feeder and trees to a concealed spot from which you can photograph – closer the better. You can also strategically clamp or tie a small tree branch on a pole (or step ladder or extra tripod, etc) very close to the feeding area to serve as a perch. The goldfinches will land on this perch before they go to the feeder so your picture taking is easier. This is a common practice in bird photography.
Also, seek out areas where wild thistle plants are growing and consider putting up a photography blind. In late summer, when the thistle’s flower heads have turned to seed, goldfinches are likely to show up looking for their next meal. A brightly colored goldfinch perched on a thistle has the potential for a great photograph!
