Monday, July 30, 2012

Some Songbirds Go Quiet for the Season & The Waxwing’s Nest

Female Cardinal working to feed her new fledglings
A cardinal fledgling hides in the foliage of a Box Elder Tree
I, like many bird enthusiasts, rely heavily on bird song to tell me what species are flitting around in the branches above me. So every year around the start of August, I always feel like I'm going deaf, as fewer and fewer birds sing. Sadly, in mid summer as the breeding season comes to a close, most species put a halt to their music making. After all, the birds produce songs to attract mates and to establish territories and as those needs fall away, they no longer have to expend energy on singing.
A male American Goldfinch sings from a high perch
An American Goldfinch nest placed 4 feet high in an Aspen sapling

This is not to say that birds become entirely mute. Contact calls, warning calls and (in the case of fledglings) begging calls are all still to be heard. Unfortunately, discerning the difference between the begging call of certain species can be problematic at best. Am I hearing begging calls of Yellow Warbler or Chestnut-sided Warbler fledglings? To answer the question I’d need to resort to the old-fashioned method of actually trying to see the bird(s).

An American Robin raises her second brood for the season
Some birds continue to sing through the second half of the summer. For the most part, these would be the late season breeders and those species that produce multiple broods. This group includes such familiar yard birds as Cardinals, Robins, Goldfinches, Song Sparrows and Common Yellowthroats. Others birds which may or may not be still breeding as late as August, may still sing at dusk. In fact, the other night, over a dozen Wood Thrushes were singing in the old woods in the early evening –I suspect that some portion of these birds were still nesting.
A Wood Thrush sings in the old woods
As the summer comes to a close, prolific songsters like the Song Sparrow and the Common Yellowthroat often continue to sing; but sometimes they’ll produce only garbled versions of their normal songs. When the breeding season ends, and as the supply of hormones in the male birds system start to peter out, the birds’ songs can lose their vitality as well as their tone.  The change is extreme enough to render these birds’ familiar songs as unrecognizable. It’s quite interesting to me how normally disparate songs like that of the Song Sparrow and Yellowthroat can begin to sound so similar minus a few hormones.
The male Common Yellowthroat continues to sing in the second part of the summer
Just lately, American Goldfinches have been singing quite beautifully in and around the woodlands and brushy meadows. For most of them the breeding season is just getting underway. This is the case with the Cedar Waxwings as well, but their gently trilled songs are very subtle and have little in common with the exuberant breeding songs of many of the other songbirds. The most exuberant sound I heard from a waxwing happened when a Blue Jay came too close to their nest. In this instance a version of the waxwing’s normally subdued trill was given in short bursts and at full intensity. –Better look out Blue Jay!
A Cedar Waxwing perches over one of the beaver ponds
The Cedar Waxwing nest containing 3 new eggs
I stopped in front of a young White Pine in one of our reforestation fields today and inadvertently frightened a waxwing off of its nest. She departed rapidly with a quick trilled note. While she was off the nest, I got to peak inside the nest and saw 3 eggs. They were pale blue and had a spattering of dark blotches. The nest itself was built of dry pine needles and twigs, and the inside was lined with fine rootlets and possibly some grass. 

No comments:

Post a Comment