Location Code: KAL17
Rufous Hummingbird (Selasphorus rufus), immature female
November 20, 2011. First
observed by homeowners (Cindy and Ken Van Den Berg) in early October 2011
and last observed on December 10, 2011. I
arrived around 9:00 a.m., and met Rich and Brenda Keith who had made the
initial contact with the homeowner about this bird.
We waited only a few minutes before the bird made an appearance,
and it was obviously a Selasphorus
based on the peach color evident on the birdís flanks.
I set up my trap (with the bird hovering near my head!) at 9:15
a.m. and caught the bird at 9:16 a.m. The bird was banded and released at
9:29 a.m. under Federal Bird Banding Permit No. 23156, and Michigan
Scientific Collectors Permit No. SC 1303.
At the home of Cindy and Ken Van Den Berg in Richland Twp.,
All data and observations in this report were made by Allen
Chartier. Also present were the homeowners (Cindy and Ken Van Den Berg),
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.
conditions: The sky was partly cloudy
and the temperature was 43 degrees. The bird was banded, weighed, and
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 This
observation was made with the naked eye from a distance of about 10-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.).
The bird was aged as hatch-year (immature) based on the presence of
shallow groovings or corrugations on about 70% of the upper mandible. This
is universally recognized as the most reliable method for age
determination in hummingbirds (Ortiz-Crespo, 1972).
The upper tail coverts and rump were entirely green. The rufous on
the base of the central rectrices (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 44.41
mm was 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 18.08 mm was
longer than adult and immature males of nominate (S.
s. sasin) Allenís Hummingbird, but within range of immature males of
the sedentarius subspecies* of
Allenís 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 had 17 clustered together in the center of the
throat (see photos), which is more frequent in females than males. There
is a tendency for immature males and immature females to have fewer
iridescent feathers, but this is extremely variable, so this birdís
throat pattern cannot really be used to support aging the bird.
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 did show both emargination and notching (see
photos), which is diagnostic for Rufous. Using Figure 3 in Stiles (1972),
the shape most closely matched figure Ab for Rufous, which would be
possible to see in photos of the free living bird, provided it spread its
tail which they rarely do unless defending food sources from other
hummingbirds. Additional support for the identification can be obtained by
measurements of the widths of two other tail feathers. In cased where r2
shows no notching or emagination, the measured widths of the central
rectrix (r1) and the outermost rectrix (r5) are the primary means to
confirm identification. One central tail feather (r1) was measured as 8.58
mm. This is around 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 4.30 mm. This is near the mid-range for immature female Rufous (3.2-4.7
mm) and 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 28.0 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
immature female Rufous. So tail length is also useful in this case. Also,
the wing measurement of 44.41 mm is above the maximum for immature females
of nominate Allenís, but is within the range for immature females of the
sedentarius subspecies of
Allenís (42.1-45.0 mm), so weakly supports the identification as Rufous
There was no body molt evident on this bird.
The outer 3 primaries (p8-p10) were old and worn and the inner
primaries (p1-p7) were recently replaced and contrasting shiny black. All
the rectrices, except r3, were fresh and unworn.
The bird had a fat code of 1 (0-3 scale) and weighed 3.64 grams, about
average for an immature female planning to overwinter.
Brief, sharp chatter when the
bird was released. More strident than Ruby-throated gives. A clear sharp
chip note when the bird was hovering nearby waiting for me to hang up the
Allenís Hummingbird is the species most similar to Rufous
Hummingbird. On this bird, the emargination and notching of the second
rectrix provided confirmation of the identification as Rufous. The widths
of both the central (r1) and outer (r5) rectrices provided additional
diagnostic and conclusive support for the identification as Rufous. Both
wing and tail measurements also provided additional support for the
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 Allenís Hummingbirds on two trips to
report was written:
This report was written on December 14, 2011 based on data and
photos taken during the banding process.
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
There are two subspecies of Allen's Hummingbird.
One is the widespread and migratory nominate subspecies (Selasphorus
sasin sasin) breeding from coastal northern
A new method to separate immature and adult hummingbirds. Auk
Identification Guide to North
American Birds: Part 1. Slate
Creek Press, CA.
Age and Sex Determination in Rufous and Allen Hummingbirds.
The Condor 74: 25-32.