Location Code:  WAY22
Location Desc.: MICHIGAN, Wayne Co., Southgate
Latitude:  N 42° 12'
Longitude:  W 083° 11'
Hummer Host: Mark Wloch

Total banded to date: 1

Click here to view written description.

Michigan Rare Bird Report

Species:  Rufous Hummingbird (Selasphorus rufus), immature female

Date & Time: November 7, 2011.  First observed by homeowner (Mark Wloch) in early afternoon on 7 November 2011, and last observed on 14 November 2011. Photos sent to me by Wloch on 7 November 2011 were indicative of a Rufous or Allen’s Hummingbird as they showed a bird with pale rufous flanks and conspicuous rufous in the tail feathers. Since the site was only 15 miles from my home (I’m used to going 100-200 miles!), I arrived at the home at 3:30 p.m. that day, set up my trap at 3:40 p.m., and caught the bird at 3:46 p.m.  The bird was banded and released at 4:00 p.m. under Federal Bird Banding Permit No. 23156, and Michigan Scientific Collectors Permit No. SC 1303.

Location: At the home of Mark Wloch in Southgate , Wayne County .

Observer (s):  All data and observations in this report were made by Allen Chartier. Also present was the homeowner (Mark Wloch) and Jerry Jourdan.

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 overcast and the temperature was 61 degrees. The bird was banded, weighed, and photographed outdoors.

Description:    The bird was first observed when captured for banding, so only in-hand data is provided here. It was aged, sexed, and identified in that order.  The proper use of Stiles (1972) for banders requires that an individual Rufous/Allen’s 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 90% 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 44.08 mm was longer than any age of male Rufous or Allen’s 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 bird’s bill appeared to have a deformity on the inside tip somewhat similar to avian pox, so might have been a temporary condition. This did not affect the exposed culmen measurement, which was 18.08 mm; longer than adult and immature males of nominate (S. s. sasin) Allen’s Hummingbird, but within range of immature males of the sedentarius subspecies* of Allen’s and shorter than the range of adult females of sedentarius. 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 did not have any on the throat (see photos), which is infrequent but can be shown by immature males and females of either species, so is somewhat useful for supporting an age determination but not the sex. 

Species:  Given that the bird was a hatch-year (immature) female, using Stiles (1972) we can determine whether this bird was a Rufous or Allen’s 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 r2’s of this individual had no emargination and no notching (see photos), not allowing confirmation of Rufous. Using Figure 3 in Stiles (1972), the shape most closely matched figure Ca for Rufous, though it also matched other figures for Allen’s, which is why measurements of the widths of two other rectrices is critical; the central rectrix (r1) and the outermost rectrix (r5) are the primary means to confirm identification. One central tail feather (r1) was measured as 8.27 mm. This is around the mid-range for immature female Rufous (7.8-9.5 mm) given in Stiles (1972), and very slightly above the upper end of the range for immature female of nominate (S. s. sasin) Allen’s (6.9-8.2 mm). But it is also near the upper end of the range for immature females of the sedentarius subspecies of Allen’s (7.3-8.4 mm). So, the width of the central rectrix provides strong but not entirely conclusive support to the identification as Rufous Hummingbird. One outer rectrix (r5) was measured as 4.34 mm. This is above the mid-range for immature female Rufous (3.2-4.7 mm) given in Stiles (1972), and is significantly broader than the maximum range for immature female Allen’s for both subspecies (max. 3.3 mm), and so provides conclusive and diagnostic support to the identification as Rufous.

Tail measurements are often not very useful.  This bird’s tail measurement of 26.0 mm is above the maximum for immature females of the nominate subspecies of Allen’s (Stiles gives no corresponding measurement for immature female S. s. sedentarius), and near the mid-range given for Rufous. So tail length is also useful in this case.

Also, the wing measurement of 44.08 mm is above the maximum for immature females of nominate Allen’s, but is within range though near he upper extreme for immature females of the sedentarius subspecies of Allen’s (42.1-45.0 mm). So wing length also somewhat supports the identification as Rufous Hummingbird.

Molt: There was extensive body molt evident on this bird.  All primaries were old and worn. On the tail, r3 and r4 appeared worn.

Fat/Weight: The bird had a fat code of 0 (0-3 scale) and weighed 3.30 grams, a bit below average for an immature female at this time of year.

Voice: None heard.

Similar Species:  Allen’s Hummingbird is the species most similar to Rufous Hummingbird. On this bird, the lack of emargination or notching on the second rectrix did not allow identification as Rufous, requiring measurement of tail feathers. The widths of the central (r1) rectrices provided strong support and the widths of the 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 nearly 60 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 Allen’s Hummingbirds on two trips to California and once recently in Arizona , handled 3 in Louisiana in February 2003, and banded Ohio ’s first Allen’s Hummingbird in December 2009.  As a trained, licensed hummingbird bander, I am familiar with all pertinent in-hand criteria for distinguishing Rufous from Allen’s Hummingbird, in addition to known field criteria for separating these species.

When report was written:  This report was written on December 14, 2011 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.

References:

Ortiz-COrtiz-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.

St.G.  1Stiles, F.G., 1972.  Age and Sex Determination in Rufous and Allen Hummingbirds. The Condor 74: 25-32.