by Bob Sargent
Let’s open up a whole new can of worms here and talk about Black-chinned hummingbird (Archilochus alexandri). The following opinions are based on both field observations and in-hand study during the winter in the Southeastern United States. It is not intended as a description of their appearance or behavior on their breeding territories. This is another case of “kissin’ cousins” and “look-alikes” in the hummingbird family. Like the discussion of Rufous/Allen’s in earlier issues of Netlines, this one will probably raise a few hackles and stir up some controversy. I’ll simply preface this discussion by saying that any experienced observer, with practice, will probably be able to sort-out Black-chinned from Ruby-throated (Archilochus colubris) by noting a combination of field marks. Whoa! Don’t jump the gun! A hummer ripping through a patch of flowers at breakneck speed or simply a ‘fly-by’ bird is not the best candidate for a detailed study of field marks. The same limitations you use on yourself when studying sparrows or shorebirds are applicable here. As with all bird species, aberrant plumaged individuals can and do occur. All of that was another disclaimer, just ahead of the good stuff.
Adult males of both species are easily separated by the color of their iridescent gorget. By the way, this iridescent gorget color is not the product of color pigment in the feathers, but rather the structure of the feathers themselves. Adult male Black-chinned will have a black chin and upper throat, bordered on the bottom of the throat by a bright iridescent purple band. Their adult male Ruby-throated cousins will have a solid iridescent ruby-red gorget. Both species will have all dark tail feathers with no white tips. On rare occasions, an adult male may have faint traces of white tips on some of these rectrices. Adult males will not be part of the following discussion.
Black-chinned and Ruby-throated are both in the same genus, Archilochus, and bear a striking resemblance to each other. Your field guides, even the newest ones, will likely show their size as identical. I beg to differ, almost all Black-chinned of the same age and sex will appear larger than their Ruby-throated counterparts. The measurement of length in hummingbirds is some pretty ‘iffy’ stuff anyway. The little suckers can sit all hunkered down with their necks pulled in or they can stretch it out like a giraffe. Consider size when you start to evaluate the bird in question, but let it be only a minor thing.
A general rule-of-thumb to remember: Black-chinned is a long-winged, long-billed, short-tailed hummingbird. Ruby-throated is shorter-winged, shorter-billed and longer-tailed. Again this is just one more of the field marks to be considered. Not only is the tail of the Black-chinned short, but they love to flick or pump it rapidly as they hover at flowers and feeders. Some Ruby-throated may also flick their tails, but not like the frenzied pumping of Black-chinned. I have never observed a Black-chinned for any length of time that it didn’t put on a display of ‘tail-pumping’ as it hovered. I don’t believe that a long tail can be pumped as fast and as easily
as a short one. This is a big deal! If the hummer in question is a big time tail-pumper, you gotta put this on the plus side for Black-chinned. Read on, you are just becoming suspicious at this stage.
Black-chinned almost always have long decurved bills. This is one of the first things that you would probably notice when viewing Black-chinned. Compared to Ruby-throated’s shorter straighter bill, Black-chinned have a snout like Jimmy Durante.
Black-chinned have long wings with blunt curved tips. Many times when Black-chinned are perched on a limb or feeder they will hold their wings slightly drooped. When this happens, the very blunt and rounded tip of the outermost primary (wing feather) is quite easy to spot with your binoculars or spotting scope. Put this one down on your checklist as a critical field mark. In contrast, the Ruby-throated will have a somewhat pointed wing tip. Their outermost primary will have only a very slight curve, and will appear narrow at the tip (see wing photos). Another thing to look for when examining the wing shape is the presence of white tufts. These will look like little cotton balls on the hummer’s side that protrude above or below the folded wings. These are very common in Black-chinned, much more so than in Ruby-throated. A word of caution, migrating fat Ruby-throated, in late summer or fall, will almost always shows these tufts protruding because of their little pudgy jelly-belly. The femoral tufts are a bonus in your list of field marks, but again only a minor one.
Both species are described in bird books as having an “emerald-green back”. They do of course, but that’s like comparing the blue sky of Alabama to the blue sky of the Rocky Mountains. Black-chinned generally have a paler green back with the color appearing more ‘flat’ and lacking strong luster. In addition, their back will often have a slight bronzy or brassy appearance. In contrast, Ruby-throated tend to have a more shimmering emerald green back with much luster even when the feathers are somewhat worn. This field mark is a biggie, especially if you‘re very familiar with the back color of Ruby-throated.
Black-chinned have a brownish gray or grayish brown crown with only a few green feathers showing. On the other hand, Ruby-throated will be emerald green on top of the head. Another word of caution: Both species can sometimes have a ‘plastered down’, crusty, dirty brown crown caused by sugars and pollen from flowers. If you know this is possible, it then becomes easier to determine which is which by using your binoculars or scope for a really close-up look. I also believe that Black-chinned tend to have a more lower sloping forehead. This, combined with their longer decurved bill gives them a more slender and less ‘stocky’ appearance than Ruby-throated. Worth noting in the field marks, but not conclusive.
The tail feathers of both species look alike in the field. Slight differences in these rectrices can be detected when the birds are in the hand, but even then these differences are subtle. To my eye, these tail feathers in Black-chinned are just a tad more ‘paddle-shaped’. In my opinion, the shape of the tail feathers will be of little value when viewing in the field.
When Black-chinned is perched and the wings are folded, the tips of the folded wing will almost always extend beyond the tip of the tail. Occasionally they will appear to be the same length. Unless the tail feathers are just emerging and do not have their full length, the tail of Ruby-throated will always extend well beyond the folded wing. Force yourself to concentrate on the tail/wing length comparison. This is a major field mark to look for in a perching bird at a feeder or in the field.
The underparts of a Black-chinned female or immature tend to be very dirty and dingy grayish white. While some variations may appear in individual birds, as a rule this is still pretty dependable. Females and most immature males will look like they have had soot smudged into the feathers on their sides and belly, appearing grungy underneath. In contrast, Ruby-throated are more likely to look whitish and clean below. Again another caution, the white underparts of Ruby-throated can become soiled and worn. This is especially true in adult females in late summer and early fall. As they incubate eggs and brood their babies they develop a worn band of feathers across the breast. The abrasion caused by the hardened rim of the nest can cause extensive wear. In addition, a hummer nest with two ‘pooping’ babies can become pretty soiled before they fledge. YUK!! You should see how messy! This is neither a major nor minor field mark, but it is worth noting when evaluating the big picture.
Finally we will address the vocalizations of both. To my tin ear, Black-chinned will call and scold in a softer and lower key than Ruby-throated. The sounds made by Black-chinned will have a softer “mew” or “thew” or “chew” quality. I believe that Ruby-throated, especially males, express themselves in a much raspier and somewhat higher pitched tone. I can almost always identify Black-chinned by its voice. If you don’t have experience with Black-chinned in the field, this paragraph will be of no value. Just save this part for later on when you are out west where the Black-chins roam, then try to concentrate on remembering the subtle differences for later comparisons with Ruby-throated.
It’s a toss up as to what species of hummingbird is most common in winter after Rufous. Black-chinned is a strong contender for runner-up. Remember, never make the identification of Black-chinned based on just one field mark, unless maybe it is a male bird with purple gorget color. With caution, you should be able to identify almost any Black-chinned at your feeder. Don’t rush, do it by the book, one field mark at a time. If after going over all the above, you still can’t say for sure, it isn’t a crime. I see many hummingbirds in the field each year that I cannot positively identify. I know of very few folks that approach being hummingbird experts. My friends Nancy Newfield, Bill Baltosser or William Calder come pretty close. I should hope to learn only a fraction of what they know.
Let’s recap what to look for:
- Black-chinned tend to be slightly larger than Ruby-throated of the same age and sex.
The size difference isn’t great, but write down your gut feeling if you know Ruby-throated pretty well.
- Black-chinned normally have longer wings and bills and shorter tails.
If the tail is much longer than the folded wing, think Ruby-throated.
- Black-chinned tend to have long and pronounced decurved bills. The bill will normally curve downward along most of it’s length.
The bill of Ruby-throated will be relatively short and straight, and rarely will it show much tendency to be downturned.
- Black-chinned tend to have lighter green backs without a lot of luster.
If the back is shimmering emerald green with a hint of blue luster, it sounds like Ruby-throated.
- Black-chinned have gray to gray-brown crowns with a few scattered green feathers.
Beware of late summer and fall Ruby-throated with sticky, stained and discolored crowns that show no green. These discolored crowns will almost always have a “plastered-down” appearance.
- Black-chinned tend to have a low sloping forehead, accented by the decurved shape of the bill. To me, this gives them a more slender overall appearance.
This is in the eye of the beholder. Strictly my own opinion. Ask someone you trust for their observation.
- Black-chinned have long wings with distinctively blunt, rounded tips. When the bird is perched this is easily seen with good optics.
The wing tips of Ruby-throated will be basically pointed and straight at the tip.
- Female and immature Black-chinned tend to have dirty and drab gray color on their underparts.
Ruby-throated will be more whitish on the breast and belly compared to Black-chinned.
Content provided by: By Bob Sargent