Rochester Hills, Michigan

Late Bloomers

 

It's July and the heat is on. Many songbird youngsters, as well as fledgling woodpeckers, birds of prey, and various other birds, left the nest long ago and are noisily following their parents around woods, marshes, and meadows. Multibrooded speicies have started their second or even third family of the year.

 For the American Goldfinch, though, nesting is only just getting started. Perched on a spent thistle flower, the olive-brown female gathers a beakful of thistle-down as material for her nest. Her colorful mate, accompanies her closely, flying to and from the nest with her as she builds.

 Goldfinch courtship actually begins much earlier in the year, when our gardens are suddenly filled with tinkling, golden flocks heralding the approaching spring. The males' merry, jingling songs more than compensate for their motley scruffiness while they change from muted winter plumage into characteristic bright yellow breeding dress.

 Singing loudly and chasing each other around, they seem as keen to start nesting as all the other spring songsters. Some pairs may indeed form during these prebreeding flocks, but then the spring courtship behavioir subsides, only to resume again later in the summer. This time it's in earnest.

 Why does the goldfinch get such a late start? Biologists believe the bird's nesting is timed to coincide with the flowering of its primary source of nest material and nestling food: composite plants, such as the daisy relatives and, in particular, thistles.

 The American Goldinch's diet is made up almost entirely of seeds year round. It even feeds seeds to its young, regurgitating a slurry of partially digested seeds into each nestlings' open beak. Most other seed-eating songbirds alter their foraging habits while breeding to feed their youngsters insects, ensuring the young get the protein they need to grow up strong. Goldfinch young, though, manage to thrive on seeds as their sole protein source.

 With some nests begun as late as August, goldfinch youngsters may not leave the nest until October. As the colorful flowers of late summer wither, throngs of goldfinch fledglings will enjoy nature's rich bounty of ripening seeds, recycling summer's fading golden hues into the gilded songesters of next year's spring.