I had the same experience as Louise - it's been a quiet winter. But I put out some seed in the snow and especially today there were new songs I've never really heard. Of course I've heard the Varied Thrust song, but this was a lot of calling and chattering, almost wren-like. Maybe it's just the first time they've been two feet from my window in groups!! Then there were Fox Sparrows, with a song that is interesting and new to me. Mostly I think of them as silent winter visitors, so that was fun too :)

Teresa Michelsen
Shelton, WA

From: Tweeters <tweeters-bounces at mailman11.u.washington.edu> On Behalf Of Wayne Weber
Sent: Monday, February 15, 2021 9:22 PM
To: TWEETERS <tweeters at u.washington.edu>
Subject: Re: [Tweeters] Song onslaught

Louise and Tweeters,

It is interesting to look at the initiation of song in spring in different groups of songbirds.

I would say that in the majority of migratory species, at least in North America, song begins at a certain time of year, regardless of whether the birds are on breeding territories or not. Singing behaviour is affected by testosterone, as are many aspects of male breeding behaviour. Testosterone production increases dramatically in late winter and early spring, as the gonads themselves enlarge. This is a direct result of changes in photoperiod (i.e., an increase in daylength). By February 1, many local species of non-migratory birds are already beginning to sing. This includes such common and familiar species as Black-capped Chickadees, Song Sparrows, and Dark-eyed Juncos. Singing increases in frequency later in February and into March, and is certainly more frequent after the birds have established territories than before.

In the case of migratory species, many of them begin to sing on the wintering grounds, before migration has started. Warblers in particular are known for singing frequently on the wintering grounds and throughout spring migration. This frequent song helps us to detect them and identify them in the spring!

Other species, for whatever reason, never or rarely sing during migration, and with rare exceptions, sing only on the breeding grounds. This includes most or all of the Empidonax flycatchers, and the "brown thrushes" (Hermit, Swainson's, Veery, Gray-cheeked, etc. ) Swainson's at least, and perhaps the other thrushes, do not start singing until well after they have arrived on the breeding grounds! Most Swainson's arrive in the Puget Sound area from about May 5 to May 15, but are silent for the first few days, and don't begin singing until about May 20 or later. In eastern Washington and southeastern BC, where the arrival is somewhat later (May 20 to 25), they don't start singing until about June 1-then all of them start singing within a couple of days! This sudden outburst of song in an abundant species is quite a dramatic event.

There are a few species, in contrast to the majority, which sing throughout the winter, although usually rather infrequently. This includes some of the sparrows like Song, White-crowned, and Golden-crowned Sparrows. The European Starling sings throughout the winter, as often as it does in the breeding season! I suspect that the hormonal control of song is different in these species than in the majority of birds.

When keeping bird notes, I have always noted which species were singing by including a little superscript "S" after my code for any species that was singing on that date. If I analyzed all of these data, I could give you more precise data on when various species sing. However, I haven't analyzed these data, and it would take a lot of time to do so!

Wayne Weber
Delta, BC
contopus at telus.net<mailto:contopus at telus.net>



From: Tweeters [mailto:tweeters-bounces at mailman11.u.washington.edu] On Behalf Of Louise Rutter
Sent: Monday, February 15, 2021 10:08 AM
To: tweeters at u.washington.edu<mailto:tweeters at u.washington.edu>
Subject: [Tweeters] Song onslaught

With the snow starting to melt, the varied thrushes in my yard all decided to start singing this morning.

I always find it odd when birds sing where they're not going to be breeding. I suppose they like to get some practice in before they get to the breeding territories.

Louise Rutter
Kirkland
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