Figure 1. This bird was initially striking by the buffiness on the edge of the feathers on the crown (suggesting HY bird; a distinctive feature of HY Black-chinneds in Idaho). The buffiness on the neck and nape, however, is abnormal for Black-chinned. While throat color is not a reliable indicator of sex in young Black-chinneds, females tend to have throats that are as pale as shown here; males are generally more stipled.
	Figure 2. The extensive buff color on the flanks is also abnormal for Black-chinned.
	Figure 3. The real eye-opener was the extent of rust / buff on the edges of the outer retrices (r2-5). This is a feature of Calliope. On a HY Calliope, this amount of rust suggests male.
	Figure 4. Black-chinneds have a more rounded, broad r1, while the r1 of Calliope is diagnostic in it's spatulate shape. The shape of this r1 is suggestive of those of Calliope, and noticeably different from typical Black-chinneds. The basal rust on r1 (though slight) is a feature not found in HY female Calliopes, so that would suggest this bird may be a young male.
	Figure 5. The wing shows a couple features suggesting Black-chinned origin. The outer primary (p10) is shaped similar to those of Black-chinneds, and the outer web widens at the curve. The very slight but noticeable notches at the end of the inner webs of the inner primaries (p4-p6) are diagnostic features of Archilochus hummingbirds, but are generally absent in HY female Black-chinneds (Baldridge 1983; pers. obs.). The presence of this feature suggests to me this bird is an immature male, even though P6 is slightly more rounded that we'd expect in a young male Black-chinned. In this case, that feather alone looks like female Black-chinned. A wing length of 47.02 mm (on this bird) is on the large side for most HY-M Black-chinneds, but is within variation for extremely large HY males of this species in Idaho where Black-chinneds tend to measure noticeably longer than those of Texas (B. Sargent & F. Bassett, pers. comm). Wing cord (along with the pale throat) does argue for female, however. This wing length is well longer than any measured male CAHU this year. Immature male BCHU wing cord (mean +/- std) for 2004 = 45.68 +/- 1.12. By definition, approximately 99% of all HY-M BCHU wing cords should fall within 3 standard deviations of the mean => between 42.32 and 49.04, which is very close to our observed range for year 2004 (range 42.47 - 48.86).
	Figure 6. Comparison of the bird in question (top) with an immature female Black-chinned (bottom). The size differential between the two birds is slight.

If you have information that supports or refutes the information posted above, I'm very interested in hearing what you have to say. Please write your thoughts to: SJPeterson@aol.com

Helpful Literature

Baldridge, F.A. 1983. Plumage characteristics of juvenile Black-chinned Hummingbirds. Condor 85:102-103.
Baltosser, W.H. 1994. Age and sex determination in the Calliope Hummingbird. Western Birds 25:104-109.
Grayes, G.R. 1990. Systematics of the "Green-throated Sunangels" (Aves: Trochilidae): Valid taxa or hybrids? Proc. Biol. Soc. Wash. 103:6-25.

Return to Hummingbird Hybrid Page