Location Code: LAK1
Michigan Rare Bird Report
Species: Rufous Hummingbird (Selasphorus rufus), immature female
Date & Time: November 10, 2010. First observed by homeowners (Kris and Michael Perry) in early August 2010 and still present as of this writing (December 13, 2010). Photos sent to me by Carl Freeman were indicative of a Rufous or Allenís Hummingbird as they showed a bird with pale rufous flanks and a few iridescent gorget feathers in the middle of the throat. I arranged with the homeowners to band the bird on November 10. I arrived around 9:30 a.m. and waited only about 10 minutes before the bird made an appearance. I set up my trap at 9:45 a.m. and caught the bird at 10:20 a.m. The bird was banded and released at 10:36 a.m. under Federal permit No. 23156, and Michigan permit No. SC 1303.
Location: At the home of Kris and Michael Perry near Irons. Lake County.
Observer (s): All data and observations in this report were made by Allen Chartier. Also present were the homeowners, Greg Bodker (a birder from Houghton Lake), and a television crew (videographer and reporter) from the local TV station in Cadillac.
Equipment: Photographed in-hand with digital camera (photos attached to this document). All measurements were made using digital calipers. Bill corrugations were determined by viewing through a 10x loupe, as they are impossible to accurately determine any other way.
Viewing conditions: The sky was mostly sunny and the temperature was 45 degrees. The bird was banded, weighed, and photographed outdoors.
Description: When the bird first made an appearance at the feeder, it was apparent that it was a Rufous or Allenís Hummingbird, based on peach-rufous on the flanks, and an irregular blotch of iridescent throat feathers that were visible in Freemanís photos that heíd sent to me. This observation was made with my 10x Swarovski binoculars from a distance of about 30-feet. The bird was then captured for banding, and it was aged, sexed, and identified in that order. The proper use of Stiles (1972) for banders requires that an individual Rufous/Allenís Hummingbird in-hand be correctly aged and sexed before a species determination can be made (B. Sargent and N. Newfield, pers. comm.).
Age: The bird was aged as hatch-year (immature) based on the presence of shallow groovings or corrugations on about 80% of the upper mandible. This is universally recognized as the most reliable method for age determination in hummingbirds (Ortiz-Crespo, 1972).
Sex: The upper tail coverts and rump were entirely green. The rufous on the base of the one central rectrix (r1) was restricted to about the basal 25%, and was completely covered by the green upper tail coverts. These characters suggested this bird was a female.
The wing measurement of 45.30 mm was about 2 mm longer than any age of male Rufous or Allenís given in Stiles (1972), so this measurement is a very strong indication that the bird was female.
The bill measurement (exposed culmen) can sometimes be helpful for determining sex. This birdís exposed culmen measurement of 18.97 mm was longer than adult and immature males of nominate (S. s. sasin) Allenís Hummingbird, but within range for both immature males and females of the sedentarius subspecies* of Allenís. So, the bill measurement somewhat supports the sex as female.
The pattern of iridescent gorget feathers on the throat can sometimes be helpful in determining the sex of Selasphorus hummingbirds. This bird had 15 clustered together in the center of the throat (see photos). This pattern could occur in either immature males or females, and the number of iridescent feathers varies considerably and is not particularly useful for supporting an age determination. There is a tendency for immature males and immature females to have fewer iridescent feathers, so this birdís throat pattern cannot really be used to support aging or sexing the bird.
Species: Given that the bird was a hatch-year (immature) female, using Stiles (1972) we can determine whether this bird was a Rufous or Allenís Hummingbird using several additional measurements and observations. The presence of notching and/or emargination on the second rectrix from the center (r2) is one feature that can often be observed in the field to confirm Rufous. The r2ís of this individual had very subtle emargination, but no notching (see photos), which is diagnostic for Rufous. Using Figure 3 in Stiles (1972), the shape most closely matched figure Cb for Rufous, which would be very difficult to see in photos of the free living bird, and are not easy to see in the photos of the bird in-hand.
In cases where notching on r2 is minimal, measurements of the widths of two other tail feathers, the central rectrix (r1) and the outermost rectrix (r5) are the primary means to confirm identification. One central tail feather (r1) was measured as 8.84 mm. This is slightly above the mid-range for immature female Rufous (7.8-9.5 mm) given in Stiles (1972), and above the upper end of the range for immature female of nominate (S. s. sasin) Allenís (6.9-8.2 mm). It is also above the range for immature females of the sedentarius subspecies of Allenís (7.3-8.4 mm). So, the width of the central rectrix provides conclusive and diagnostic support to the identification as Rufous Hummingbird.
One outer rectrix (r5) was measured as 3.89 mm. This is broader than the maximum range for immature female Allenís (max. 3.3 mm) for both subspecies, and so provides conclusive and diagnostic support to the identification as Rufous.
Tail measurements are often not very useful. This birdís tail measurement of 28.1 mm is above the maximum for immature females of the nominate subspecies of Allenís (Stiles gives no corresponding measurement for immature female S. s. sedentarius), and even slightly above the maximum given for Rufous. So tail length is also useful in this case.
Also, the wing measurement of 45.30 mm is above the maximum for immature females of nominate Allenís, and is slightly above the upper extreme for immature females of the sedentarius subspecies of Allenís (42.1-45.0 mm), so also supports the identification as Rufous Hummingbird.
Molt: There was no body molt evident on this bird. The outer 4 primaries (p7-p10) were old and worn; p6 appeared to be about 95% fully grown as there was a remnant of a sheath at its base, and the remaining inner primaries (p1-p5) were recently replaced and contrastingly shiny black. All the rectrices were fresh and unworn.
Fat/Weight: The bird had a fat code of 0 (0-3 scale) and weighed 3.39 grams, about average for an immature female planning to overwinter.
Voice: Brief, sharp chatter when the bird was released. More strident than Ruby-throated gives.
Similar Species: Allenís Hummingbird is the species most similar to Rufous Hummingbird. On this bird, the subtle emargination of the second rectrix provided confirmation of the identification as Rufous, albeit this was only discernable in-hand. The widths of both the central (r1) and outer (r5) rectrices provided diagnostic and conclusive support for the identification as Rufous. Both wing and tail measurements also provided additional support for the identification.
Experience: I have seen hundreds of Rufous Hummingbirds in several states, banded 55 in Michigan, Ohio, Indiana, and Ontario, and handled ~35 in Louisiana in February 2003 with Nancy Newfield, and handled about a dozen in Arizona in July 2006 helping other banders. I have seen several Allenís Hummingbirds on two trips to California and once recently in Arizona, handled 3 in Louisiana in February 2003, and banded Ohioís first Allenís in December 2009. As a trained, licensed hummingbird bander, I am familiar with all pertinent in-hand criteria for distinguishing Rufous from Allenís Hummingbird, in addition to known field criteria for separating these species.
When report was written: This report was written on December 13, 2010 based on data and photos taken during the banding process.
References consulted: None were consulted while observing the bird in the field, nor were any used to write notes in the field or to write this report. Stiles (1972) and Pyle (1997) were available during the banding of the bird.
* There are two subspecies of Allen's Hummingbird. One is the widespread and migratory nominate subspecies (Selasphorus sasin sasin) breeding from coastal northern California to coastal southern California and mainly migrating southward into Baja California, Mexico. The other is a more range-restricted and generally non-migratory subspecies (S. s. sedentarius), breeding on California's Channel Islands and the adjacent mainland (around Los Angeles). But sedentarius presents some problems, because it is intermediate between S. s. sasin and Rufous in some characters. And, while sasin has a shorter bill than Rufous, sedentarius has a longer bill! If sedentarius were entirely sedentary, this would not be an issue. But, I've been told (N. Newfield, pers. comm.) that the first specimen of Allen's Hummingbird collected in Louisiana actually fits sedentarius! So, however remote the possibility, sedentarius must also be considered.
Ortiz-Crespo, F.I. 1972. A new method to separate immature and adult hummingbirds. Auk 89: 851-857.
Pyle, P. 1997. Identification Guide to North American Birds: Part 1. Slate Creek Press, CA.
Stiles, F.G. 1972. Age and Sex Determination in Rufous and Allen Hummingbirds.The Condor 74: 25-32.