{"id":4764,"date":"2014-07-21T14:57:34","date_gmt":"2014-07-21T20:57:34","guid":{"rendered":"http:\/\/earbirding.com\/blog\/?p=4764"},"modified":"2014-07-21T16:27:34","modified_gmt":"2014-07-21T22:27:34","slug":"how-to-identify-a-timberline-sparrow","status":"publish","type":"post","link":"http:\/\/earbirding.com\/blog\/archives\/4764","title":{"rendered":"How to Identify a Timberline Sparrow"},"content":{"rendered":"\n\n\n\n
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\"Timberline<\/a>
Timberline Sparrow, Mount McIntyre, Yukon. This individual was an especially boldly marked and patterned individual. Copyright Andrew Spencer.<\/figcaption><\/figure><\/td>\n<\/tr>\n
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\"Brewer's<\/a>
Brewer’s Sparrow, Mojave Desert, California. Copyright Luke Seitz.<\/figcaption><\/figure><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

It’s hard to deny – among many birders there is a preconception that sparrows are brown and boring looking. \u00a0And while I would argue that point for many of the species in the group, it isn’t very easy to defend Brewer’s Sparrow (Spizella breweri<\/em>). \u00a0It’s a small, brown, and subtly marked bird that doesn’t stand out much when you see it. \u00a0But just wait until you are standing on a sage flat in the pre-dawn and\u00a0hear<\/em> a Brewer’s Sparrow! \u00a0There are few auditory experiences in the west as sublime as being out in the crisp, cool air, surrounded by the smell of sagebrush, and hearing the tinkling buzzes of Brewer’s Sparrow all around you.<\/p>\n

In addition to having one of the best voices in the west, Brewer’s Sparrow also has an interesting taxonomic facet to its name. \u00a0The nominate\u00a0breweri<\/em> subspecies is familiar to most anyone who birds in the appropriate habitat. \u00a0Less well known is that there is another subspecies –\u00a0taverneri –\u00a0<\/em>that was first described as a separate species from far to the north of most Brewer’s Sparrows (Swarth and Brooks 1925<\/a>). \u00a0Unlike the nominate subspecies, it is restricted to stunted, willow-dominate thickets right below treeline – hence the common name of “Timberline” Sparrow. \u00a0It was later lumped with Brewer’s Sparrow, but recent morphometric and genetic studies have again raised interest in the form (see Klicka et al 1999<\/a>). For a long while conventional wisdom said that Timberline Sparrow occurred only well north of Brewer’s, in an isolated range centered around southern Yukon. \u00a0But as more people studied the bird it was found to also occur near treeline further south, first in the Canadian Rockies, and then in Montana. \u00a0Birds have been found in similar habitats even further south, to at least southern Colorado, but it is less well known what to make of these birds (more on this later in the post).<\/p>\n

\"Timberline<\/a>
Timberline Sparrow, Jasper National Park, Alberta. This individual (a female) was among the most dully patterned individuals I saw, closest to Brewer’s in appearance. Copyright Andrew Spencer.<\/figcaption><\/figure>\n

Before I dive into the vocals of these birds, a bit on the visual identification. \u00a0As Brewer’s Sparrow doesn’t have much in the way of obvious field marks under the best of circumstances, it shouldn’t come as any surprise that telling Timberline from the nominate isn’t easy by any means. \u00a0The most often cited field marks are usually bill size (Timberline has a longer but thinner bill), strength of the face pattern and crown streaking (noticeably stronger in Timberline), overall color (noticeably grayer in Timberline), and sometimes some faint streaking on the flanks or sides of the chest in Timberline. \u00a0All of these marks are hard to use in isolation, at least for someone without a lot of experience with both forms. \u00a0Personally, I believe that if I spent time closely looking at migrant or wintering Brewer’s Sparrows I might be able to find birds that I have a strong suspicion are Timberlines, but that I wouldn’t be able to make a claim with certainty.<\/p>\n

Enter vocals. \u00a0Differences in the song between Brewer’s and Timberline are the most often cited difference between the two. \u00a0Before getting into the nitty-gritty of it all, though, we need a bit of a primer in the sounds that Brewer’s Sparrow (sensu lato) make – it’s more complicated than just song and call. \u00a0That wonderful dawn chorus I mentioned in the intro to this post is what is known as the “long song” – a successive series of different trills, typically starting out very high-pitched and then descending into a long string that can sometimes last 20 seconds or more. \u00a0Mostly given very early in the morning and late in the evening, it can sometimes be heard at other times of the day but generally less often. \u00a0Below is an spectrograph of long song from Mesa County, Colorado, to demonstrate the structure of the voc.\"Brewer's<\/a><\/p>\n

The other song of the species is appropriately known as the “short song”. \u00a0This vocalization, much shorter than long song, is typically comprised of one to three different trilled phrases, each phrase most often (but not always) even in pitch, but different in pitch from the previous one. \u00a0It is also one of the most variable songs in the west – some birds can sound startlingly like Chipping Sparrow, while others incorporate elements almost reminiscent of Prairie or Blue-winged Warbler songs. When you hear a Brewer’s Sparrow during daylight hours it is much more likely to be giving this vocalization than the long song, though again there are exceptions to this. \u00a0Most Brewer’s Sparrows only have one short song that they give, whereas long song can be variable in terms of which trilled elements they include. \u00a0If you want to read more on the different song types, Arch McCallum has a page dedicated to the topic here<\/a>.<\/p>\n

Like most other sparrows, Brewer’s also has various calls – flight call, chip call, twitter, etc. \u00a0I don’t really go into those here, in part due to very small sample size available from Timberline Sparrow of these calls, and also since I don’t personally believe that they can be identified to form.<\/p>\n

Of the two song types, it is long song that I believe is most readily distinguishable between the two forms. \u00a0The “classic” long song of\u00a0breweri<\/em> typically sounds very buzzy throughout, descending from very high-pitched, insect-like buzzes to lower pitched buzzes, but rarely having anything that one would describe as “musical” about them. \u00a0This is due to the broadband nature of all of the elements of the song. \u00a0Most phrases in the long song are made up of two alternating notes that comprise the buzz, and in nominate\u00a0breweri<\/em> both of these elements are broadband, or if one is less so then the broadband one dominates. \u00a0Below are several examples of long song from\u00a0breweri<\/em> from around their range.<\/p>\n\n\n\n
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