UNUSUAL HUMMINGBIRD FOR IDAHO

ANNA'S HUMMINGBIRD -- Calypte anna

November 2001 - May 2002, Moscow, Latah County

While not an unheard of hummingbird in Idaho, Anna's certainly is deserving of attention in this state. On the official Birds of Idaho Field Checklist, Anna's Hummingbird is listed as rare and local statewide during migration. At the turn of the century there were typically at most two or three reports per year. With increased awareness and a larger number of observers reporting birds to this website, I believe the number of reports will continue to grow. The origin of these birds is uncertain, but it is thought that fall sightings may be wanderers from breeding sites in the Pacific Northwest -- perhaps Seattle, WA or Vancouver, BC.

In late 2001, I received word that a lethargic hummingbird which had been on site since about 19 September had been captured on 21 November at a private residence near Moscow, Idaho and taken to Nancy Maxeiner in nearby Viola. I contacted Nancy and learned that her position as a vet / rehabber allows her to keep these birds, which was determined to be a potential Anna's Hummingbird. She was interested in knowing more about this species, and was interested in allowing me to band her bird if I could make it up to Moscow -- which I wasn't planning to do until April of the following year. She was keeping the bird in her home office -- free-flying, with a hummingbird feeder and fruit flies for nourishment, and said she didn't intend to release it in the spring, so we made plans for an April banding session.

While I am generally not in favor of "rescuing" birds from the cold (I feel that birds have more ability to surivive on their own than we give them credit for; and furthermore nature often has a way of doing fine without human intervention on the population-level), in certain cases rehabbing wild birds may benefit the individual bird itself. And banding those birds already brought into captivity may help to certify this success in the (admittedly unlikely) event that they are encountered again.

The photos showed the bird to be a male Anna's Hummingbird molting into adult plumage. By the time I handled the bird on 28 April 2002 (photos below), he had pretty much completed gorget molt and was clearly a second-year male Anna's. He was thus aged "SY" (Second Year), meaning he had hatched during the 2001 breeding season.

Many thanks to Nancy Maxeiner for allowing me to band and study her hummingbird during it's stay.

MEASUREMENTS in hand: Exposed culmen: 17.36 mm; Wing cord: 46.41 mm; Tail length: 31.0; Mass: 4.1 grams; Fat score: 1 on scale of 0-4.

PHOTOS (all © 2002 Stacy Jon Peterson; taken with a Canon Powershot Pro90IS camera, contrast enhanced / sharpened, etc., on MS Picture It! Photo version 7.0)

Figure 1. The Anna's Hummingbird had been living in Nancy's office, often perching on a bookshelf near the ceiling. This photo shows the elongaged gorget feathers on the throat, the long bill, and the long tail that all support the identification of Anna's Hummingbird -- wihch is further supported by the morphometric measurements. The gorget feathers are not nearly as extensive as would be expected in a fully adult Anna's, providing further evidence that this bird was a second-year bird.	Figure 2. The back of the bird shows a somewhat raged gorget / grown -- a few green feathers intermixed with the colored ones behind the eye. The tail was adult male plumaged, but the tips of the outer retrices were ragged, likely due to being held in captivity. Anna's and Costa's Hummingbirds are the only common North American species that routinely have significant numbers of irridescent gorget feathers on the crown.
Figure 3. Though overexposed radically by flash, this picture shows the gorget color fairly accurately, as well as the extent of color on the head. A very few elongated gorget feathers can be seen at the side of the neck, just above my thumb. The host states that the bird had recently attained those feathers, and while no further pinfeathers are visible, it is likely that more colored gorgets will be achieved later.	Figure 4. The wings were still in active molt, as shown by this photo. Normally this species molts in the fall, and not in April! I would guess that this severely delayed molt was due to being in captivity. Molt is determined my hormonal activity, which in birds is often effected by changing daylength. If the light cycle of the room in which the bird was held was not synchronized to actual daylength, this may effect molt. The rounded tip to the retained top secondary is further evidence of this bird's age as Second Year (in April 2002). Rounded secondaries are Hatch Year features in Anna's Hummingbirds -- double concave-tipped secondaries are adult features.
Figure 5. This bird weighed a healthy 4.1 grams (tared scale), typical of this species.