Sunday, December 12, 2010

Old Goldie

Since 2002, I have been banding birds in my back yard in Inkster, Wayne County, Michigan where, since we moved here in 1987, a total of 140 species have been recorded in, over, or from the yard. Initially only hummingbirds were banded, but in 2004 I began to band all birds in the yard to study populations and winter site fidelity. In general, in "winter" I band three days a month from October to March, and since the yard is so small, set up only two nets in the back, and two traps in the front. Through 2009, a total of 2201 birds of 30 species has been banded, not too bad for a very urban site, 5 miles northeast of Detroit Metropolitan Airport (the red square on the screen capture from Google Earth below).

A number of interesting species have been banded over the years, including 3 Cooper's Hawks, Sharp-shinned Hawk (1 in 2010), a total of 114 Ruby-throated Hummingbirds (2002-2009), a Red-breasted Nuthatch, 3 Brown Creepers, 5 Carolina Wrens, Ruby-crowned Kinglet, Hermit Thrush, Black-throated Blue Warbler, Field Sparrow, Common Redpoll (2008), and 19 Pine Siskins (1 in 2008, 18 in 2009). But more than half of all birds banded (1200+) have been American Goldfinches. It is interesting to see the population ups and downs over the years, but it is the recaptures that are even more interesting. Over the years, I've caught two different American Goldfinches banded in Dearborn, 5-6 miles away, by Julie Craves. One of the goldfinches I banded in the yard was found in spring near Hamilton, Ontario. Each winter, several goldfinches banded in previous winters return, and birds that are 3-4 years old are not too uncommon.

Last week, however, I caught an adult male goldfinch that I had originally banded as a second-year male on March 9, 2004. This means he was hatched in summer 2003, so was 7 years old this summer. This is by no means the oldest American Goldfinch on record. The Bird Banding Lab maintains a web page of longevity records, where they show the record for American Goldfinch as 10 years, 5 months. The standard way of determining a recaptured bird's age is to presume it was fledged in June. This works well for most songbirds, but late-nesting species like Cedar Waxwings and American Goldfinches may not fledge until July or August (or even early September). But even though he isn't the oldest, it appears he is among the oldest (maybe 7th oldest), and so I've nicknamed him Old Goldie. Oddly, unlike many other goldfinches that are recaptured in the yard, this bird has not been captured even once since he was originally banded in 2004. Maybe he'll change his pattern and return in a couple years.

This isn't Old Goldie, but another winter adult male American Goldfinch.

Friday, December 3, 2010

Three December Hummingbirds in Michigan

Michigan in December is not normally thought of as a welcoming place for hummingbirds. But on December 1, 2010, there was not only one, but THREE hummingbirds of THREE species in the state. Most readers of this blog will know that only the Ruby-throated Hummingbird breeds here, and is the only expected species at any time.

At Grand Marais, in the Upper Peninsula, two homeowners had taken down their feeder on the 1st or 2nd of October because they had not seen a Ruby-throat in about ten days. The next day, it became apparent to them that there were still two hummingbirds present and they put the feeder back up. Over the course of the next two weeks, they became suspicious that the adult male might not be a Ruby-throat but something else. On October 24, they took his photo and by October 27 several local birders had confirmed he was actually an adult male Anna's Hummingbird, a first ever in Michigan! Others have taken better photos, but below is one that I took of him on an overcast day, November 1, 2010. His pose in this photo is characteristic of an Anna's Hummingbird singing, which he was noted to do rather frequently from this favorite perch in an apple tree.

The other bird was also photographed around that time, and was assumed to be a female Ruby-throated. But closer examination of the photos by me and others suggested that this hummingbird was also an Anna's Hummingbird, likely a female! Determining the age of female Anna's Hummingbirds is difficult without having the bird in-hand, or good photos of the spread tail. My own photos, one below, suggests to me that she is an adult as it appears there is white on the second rectrix, which an immature might not show.

The adult male Anna's Hummingbird was last seen on November 11. As this species begins nesting as early as December in California and February in southwestern British Columbia, his departure at this time makes sense. The female was still on-site on December 1, despite the temperatures dipping into the 20s and 30s, and a snow accumulation which is expected this time of year in the Upper Peninsula. It is worth noting that an Anna's Hummingbird spent the entire winter of 2009-2010 in the Alaska Panhandle.

On November 10, I traveled to the northern Lower Peninsula, near Irons in Lake County, where homeowners were reporting a hummingbird that, based on photos sent to me by local birders, was either a Rufous or Allen's Hummingbird. Although there are 26 accepted Michigan records of Rufous Hummingbird between 1974-2009, only two have been from the Upper Peninsula and only three from the northern Lower Peninsula (two in 1988 and one in 1989). There are an additional 7 accepted records of Rufous/Allen's Hummingbird (species undetermined) between 1988-2007, of which one was from the northern LP and the rest from the southern LP. Upon capturing and banding this hummingbird, it was determined that she was a hatch-year (immature) female Rufous Hummingbird.

The diagnostic character for Rufous Hummingbird is often the presence of "notches" on the second tail feather (centrals are the first). But as is often the case, in my experience, with immature females this notching is very subtle or even non-existent (see spread tail photo below). In this case, it comes down to the measured widths of the first (central) tail feather and the fifth (outer) tail feather. In these measurements, she was within the range of Rufous and outside the range of Allen's, which measures narrower, but in some cases by only a fraction of a millimeter.

This hatch-year female Rufous Hummingbird was still present on December 1, 2010. The homeowners have nicknamed her "Tinkerbell".

On October 18, 2010, a homeowner near New Boston, Wayne County in Michigan's southern Lower Peninsula, noticed a hummingbird at a feeder he hadn't yet taken down although he hadn't seen a hummingbird for more than a week. After photos were obtained by local birders in early November, it was determined that she was a female and/or immature Ruby-throated Hummingbird. This species lingers into October in varying numbers every year in Michigan, but there are only about 10 confirmed records for November. Daily reports kept coming in, and I personally went to see this bird on November 12, when I guessed that she was an adult female based on the state of her molt. She seemed quite active and came in to the feeders several times, but I never got photos of her perched on the feeder.

On November 26, I went to the home to band her, and to assess her condition. I confirmed that she was an adult female, and that she had a good amount of body fat. This was good news suggesting that she should migrate eventually. Her weight was 3.91 grams, which is well above many that I band in late September, and significantly above the typical "non-fat" weight of about 3.25 grams. Since the temperature when I banded her in the afternoon had finally risen to 32 (from 25 in the morning), I was reluctant to take photos of her in-hand, so released her quickly. She returned to the feeder within 20 minutes. A photo of her perched in her favorite Witchhazel tree shows the worn tail tips, which is a clue to her being an adult.

Her presence on November 26 tied the record late date for the species in Michigan, as there had been one on November 26, 2009 in southwestern Michigan (Allegan County), and one from Halloween through November 26, 2007 in Marquette, amazingly in the Upper Peninsula. But she continued on and was still present on December 1.

It has been an amazing fall season for hummingbirds in Michigan.