[Tweeters] White-crowned sparrow singing

Joshua Glant josh.n.glant at gmail.com
Mon Nov 9 07:10:09 PST 2015

Hello Mrs. Wong,

What you're experiencing is likely autumnal recrudescence! Recrudescence is a behavioral phenomenon in some birds that happens because of hormonal changes. In many birds, hormones are influenced by the length of light in a day, called the photoperiod.

In fall, the photoperiod is of similar length to that in spring, which creates sort of a hormonal "false spring" that compels these birds to sing, as well as act territorial and aggressive. Just last week, I was walking home when I heard a robin give a brief warble of song. For just a moment, it felt like spring. And then I remembered how cold it was and how yellow the trees were!

Yesterday, actually, I heard and saw a Hutton's Vireo singing in my yard. I'm not sure if this is recrudescence, as my lifer Hutton's Vireo was heard singing this February, but it was cool either way!

Good birding, Joshua Glant

Mercer Island, WA

Josh.n.glant at gmail.com

> On Nov 8, 2015, at 12:31 PM, Izzy Wong <gobirder at gmail.com> wrote:


> Hi Tweeter types,


> We've had a White-crowned Sparrow singing in our yard for a few weeks. I love it, although it doesn't sound like the familiar complete song I'm used to hearing. I don't believe I've ever heard one singing this late in the year. How common is this autumnal White-crowned Sp. singing?


> Also, the Pine Siskins are back as of yesterday. And we noticed a brief visit of Evening Grosbeaks, as well.


> Lately, our yard has been quite the place to be, with lots of birdies showing up to the party. Seems like fun for them until one of the neighborhood pussy gatos crashes the party.


> good birding to all,

> isadora wong

> seattle, wa

> gobirder at gmail.com




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