I spent the weekend in the company of this presumed hatch
year (HY) male Ruby-throated Hummingbird.
I had
been resigned to thinking my feeders would no longer host anymore hummingbirds
for the year when two appeared in the yard on Friday afternoon. I spent time photographing
and digiscoping one of the birds which I concluded was likely a hatch year male.
While aging Ruby-throated Hummingbirds in the field is challenging since
seeing bill corrugations (the reliable method for aging) requires microscopic views, several features lead me
to believe the bird in question is a HY male. For starters, the bird had
two red-gorget feathers on the throat which nearly always is a indicative of a HY male. Secondly, the head and body feathers were
buff-edged which is associated with HY birds of this species at this time of year.
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| Ruby-throated Hummingbird showing 2 red gorget feathers |
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| Showing the buffy edged head feathers during preening |
Generally speaking, caution should be employed in attributing age and sex to Ruby-throated Hummingbirds during late summer and fall via field observation. By October, the full red-gorgetted adult males have long left the state with
most if not all birds falling into the nebulous female/hatch year category. While
it is generally true, birds with minimal to no dusky markings on the throat are
likely females this feature is not the sole determining factor for sex per my banding training with the Great Lakes HummerNet team led by Allen
Chartier. Furthermore, while a few red gorget feathers often point to a bird
being a HY male, Pyle notes in the Identification Guide to North AmericanBirds, occasional AHY females can have one to a few iridescent red feathers in
the throat. Hence the waters of age and sex become quite muddy when observing
this species in the field during late summer/fall.
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| Bill corrugations (wrinkles on bill) ~90% of bill in this example indicate HY bird |
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| Throat pattern on a HY male RTHU |
When banding, once age is determined by bill corrugations
(wrinkles on the bill), for a HY bird sans the red gorget feathers, often the wing cord and culmen
measurements are sufficient for determining sex. The males are shorter on both measurements. When these
measurements fall in an overlap range between the sexes, the shape of primary 6
(p6) is used to determine the sex. On a HY male Ruby-throated Hummingbird, p6
is attenuated to sharp point and the outer vane is quite narrow. This is seen
well in the digiscoped images I captured of my weekend visitor (see image
below). However note in an AHY female, p6, though less pointed is quite similar.
In contrast a HY female’s p6 is rounded at the tip with the outer vane being
wider.
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| Attenuated p6 on my weekend visitor |
Another characteristic to consider in separating HY males
from HY females is the shape of the outer retrix (r5). HY males have a more
tapered outer retrix. In the absence of
knowing he bird’s age, again there is overlap in the outer retrix shape of a HY
male versus AHY female. Same goes for throat pattern. Not all HY males will have
red gorget feathers and as noted above, some AHY females can actually have one
to a few red gorget feathers. Hence the earlier caution stands, in the absence
of knowing the age of a Ruby-throated hummingbird (most reliably determined by
bill corrugations under magnification), Ruby-throated Hummingbirds that are not
AHY males with full red gorgets should typically be left identified to species only in the field. However with careful observations and photographs one may be able to age and sex.
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| Somewhat attenuated outer retrix Shape on the weekend visitor is consistent with HY male or AHY female |
But back to my visitor which I’m calling a "he" since after
handling a couple hundred Ruby-throated Hummingbirds this summer, I feel fairly confident this is a young
male. He spends most of his down time in the Washington Hawthorne. It’s both
close to some of the preferred feeders and is great cover with its 1-2
inch thorns that offer some protection against avian predators like the local
Cooper’s Hawk. Though I’m not sure a Cooper’s would be satisfied with a measly
hummingbird meal that is the equivalent weight of a penny.
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| Hanging out in the Washington Hawthorne |
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| Washington Hawthorne |
While others in Wisconsin report their hummingbirds
preferring flowers and bugs over nectar feeders in recent days, mine fed
consistently on the feeders all day Saturday. Infrequently I saw him foraging
for insects in our large pine tree and once nectaring on the Turtle Head and
Anise Hyssop.
Despite the cold temps in
the mid 30s the bird still mustered the energy on Saturday to chase away one of
the resident Chickadees on several occasions.
It was nice to have this little distraction between chores when my desire to go out on some major birding foray in the cold damp weather
was lacking. Time will tell if the little bugger will be here tomorrow.
I’m still holding out hope, with seven feeders cleaned and refreshed every 2-3 days, that a vagrant hummingbird will find its way to my yard this year!
I’m still holding out hope, with seven feeders cleaned and refreshed every 2-3 days, that a vagrant hummingbird will find its way to my yard this year!
