{"id":2521,"date":"2010-11-23T22:48:17","date_gmt":"2010-11-24T04:48:17","guid":{"rendered":"http:\/\/earbirding.com\/blog\/?p=2521"},"modified":"2016-11-25T08:23:14","modified_gmt":"2016-11-25T14:23:14","slug":"do-violet-green-swallows-sing","status":"publish","type":"post","link":"http:\/\/earbirding.com\/blog\/archives\/2521","title":{"rendered":"Do Violet-green Swallows Sing?"},"content":{"rendered":"
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Violet-green Swallow, Nicasio, CA, 6\/6\/2008. Photo by Len Blumin (Creative Commons 2.0).<\/figcaption><\/figure>\n

The Violet-green Swallow has long been one of my favorite birds.\u00a0 Perhaps that’s because it is the only one of the seven widespread North American swallow species that I didn’t see regularly when I was growing up in eastern South Dakota.\u00a0 Perhaps it’s the wonderful way that the colors blend on its iridescent back.\u00a0 Perhaps it just reminds me of my beloved Rocky Mountains.<\/p>\n

At any rate, most of the reasons I like Violet-green Swallows have always had to do with what they looked like, not what they sounded like.\u00a0 I was fairly familiar with their calls, or so I thought, but I had never really listened to them closely.<\/p>\n

Even so, I was astonished to find that the current scientific literature says that Violet-green Swallows don’t sing at all.\u00a0 “I detected no recognizable, repeating series of syllables which could be interpreted as a song,” wrote Charles Brown in a 1983 paper<\/a> in the Wilson Bulletin.\u00a0 An undergraduate at the time of the research, Brown is now legendary as a swallow researcher<\/a>, having spent two decades studying Cliff Swallow coloniality in Nebraska.\u00a0 But after writing the BNA account<\/a> on Violet-green Swallow in 1992, Brown apparently hasn’t published anything further on the species.\u00a0 Nor does anyone else seem to have studied its vocalizations.\u00a0 And so, according to the literature, Violet-green Swallows don’t sing.<\/p>\n

Really?\u00a0 No song?<\/h4>\n

It struck me as unlikely that Violet-green Swallows should lack a song, first because I thought I had heard complex song-like vocalizations from them, and second because the Tree Swallow, a close relative of the Violet-green, definitely sings<\/a>.\u00a0 It’s rare for one member of a species pair to sing and not the other.\u00a0 (However, it’s not unprecedented.\u00a0 Eastern Bluebirds sing a complex, melodious song<\/a>; Western Bluebirds reportedly just string call notes together<\/a>.)<\/p>\n

So I went looking through my collection of Violet-green Swallow recordings.\u00a0 Interestingly, most of my recordings matched Brown’s original findings: during the day, the species tends to give three kinds of calls, and even though some of them sound “complex” and I had taken them for song, it appears that none of them are stereotyped–meaning they’re not carbon copies of one another.\u00a0 Instead, each rendition of a call varies slightly from all the others, like in the calls of House Finches or Rosy-Finches.\u00a0 As Brown noted, if these calls were going to be strung together in some kind of song, one would expect to see stereotyped versions, possibly repeated in some kind of predictable pattern.<\/p>\n

However, note the caveat in what I said above: during the day<\/em><\/strong>.\u00a0 Some swallow species (including Tree Swallow and Purple Martin) sing dawnsongs that apparently differ significantly from anything they say when the sun’s up.\u00a0 Brown’s work did not reveal the existence of a dawnsong in Violet-green Swallow, but it did note the passing mention of “predawn song-flights” in The Birder’s Handbook<\/a> and “apparent chee-chee calls” starting as early as 2:20 a.m., according to Bent’s Life Histories<\/em>.<\/p>\n

And that led me to a most interesting recording in my collection.\u00a0 At 4:20 in the morning on the 2nd of\u00a0 July, 2008, when the sun was only barely lighting the eastern horizon, I was hiking with a friend up the Loch Vale trail in Rocky Mountain National Park, hoping to reach a Black Swift nesting site before dawn.\u00a0 Just as we reached the Loch, I heard chirping from far overhead, and I immediately turned on my recorder, hoping to catch a Black Swift coming off its night roost.\u00a0 But no: the chirping was too regular, too relentless, not high-pitched or clear enough.\u00a0 The bird was completely invisible as it circled, singing endlessly against a backdrop of stars, but I was pretty sure it was a Violet-green Swallow.\u00a0 Here is a snippet of the recording:<\/p>\nhttp:\/\/earbirding.com\/blog\/wp-content\/uploads\/2010\/11\/VGSWdawnS-NDP2008-26-51.mp3<\/a><\/audio>\n

The bird went on like this for at least several minutes without pausing.\u00a0 When I first looked at the spectrogram of the above snippet, it looked like the daytime calls had: a jumble of similar notes, each slightly different than the last, showing no apparent rhyme or reason.\u00a0 But then I zoomed in and started looking very carefully, and sure enough, a pattern emerged:<\/p>\n

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The calls are <\/em>stereotyped: all the “A” phrases are basically identical to one another, as are the “B” phrases, etcetera.\u00a0 Furthermore, although the order is variable, there’s a strong tendency to stick to a couple of basic patterns.\u00a0 In other words, this is classic song, crystallized and rule-bound, no matter how disordered it sounds to our slow human ears.<\/p>\n

You may not want to give them any prizes for their melody, and you may not even hear them unless you rise long before the sun.\u00a0 But make no mistake: Violet-green Swallows do <\/em>have a song–one that seems to have gone almost unnoticed until now.<\/p>\n","protected":false},"excerpt":{"rendered":"

I was astonished to find that the current scientific literature says that Violet-green Swallows don’t sing at all. It struck me as unlikely, so I went looking through my collection of Violet-green Swallow recordings.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[103],"tags":[177,176],"class_list":["post-2521","post","type-post","status-publish","format-standard","hentry","category-behavior","tag-tachycineta-thalassina","tag-violet-green-swallow"],"_links":{"self":[{"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/posts\/2521","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/comments?post=2521"}],"version-history":[{"count":13,"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/posts\/2521\/revisions"}],"predecessor-version":[{"id":5061,"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/posts\/2521\/revisions\/5061"}],"wp:attachment":[{"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/media?parent=2521"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/categories?post=2521"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/earbirding.com\/blog\/wp-json\/wp\/v2\/tags?post=2521"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}