? To a large extent, birding is nothing but the study of feathers. Except for a bird’s bill, eyes and legs, its entire body is covered in feathers. These miraculously evolved keratin structures not only provide waterproofing, insulation, protection, and of course the power of flight, but also give a bird its shape, colours and markings.
All birds have feathers, and no other animals but birds have feathers. But how many feathers do birds have? This a rather complex question, because it depends on how you define feathers – would you classifiy tiny filoplume bristles with a sensory function as feathers? And how would one count the rather undifferentiated downy undercoat of some birds? At the other side of the spectrum are the large flight and tail feathers – these are easy enough to count, and are relatively standard in birds. But it also depends on the species. Some hummingbirds have only a few hundred feathers – around 940 on a Ruby-throated Hummer for example. Some birds, and particularly those which require extensive waterproofing, have a lot more. Tundra Swans can have more than 25,000 feathers, with 70% of those on the neck and head. Generally larger birds have slightly more feathers (though not in proportion – their indivual feathers are just larger, instead of more in number), and many birds have more feathers in winter than in summer. Most songbirds (passerines) have between 1,500 and 2,600.
…and thanks Neil’s mom for the tupperware!
I set out to test this claim on a beautiful little Black-throated Canary, Crithagra atrogularis, which my friend Niel Cillie gave to me (and thanks Neil’s mom for the tupperware!). This little guy was in perfect condition, depsite having spent the best part of a year in my freezer. With our move to Langebaan fast approaching, my wife made it very clear that I have to get rid of all the bird specimens still hiding between the fronzen peas and ice-cream. From personal experience while I still worked at a natural history museum, I know that making a study skin of such a tiny bird is a fool’s game. And so came my naive decision to “deconstruct” the bird by pulling out, classifying and counting all of its feathers. It’s been a long day…
One of the most important steps in bird identification is learning to distinguish feather groups. Unfortunately most beginners, and many advanced birders, ignore diagrams like those shown below; however, a thorough understanding of bird topography will allow you to observe and appreciate birds in greater detail; contrary to what one might expect, mastering this skill will also greatly simplify birding. This is because feathers are not distributed randomly across the body, but instead grow in very specific feather tracts (or pterylae). The placement of feather groups, and the number of feathers in each, are surprisingly similar across all birds. It is therefore possible to practise recognising different feathers on any bird, from a canary to crane.
Finding a freshly dead bird in good condition also presents a very valuable opportunity for close up study. Sure it’s a little morbid, but at least something good will come of the bird’s death. If you’re squeamish, wear gloves. You could also attend a bird ringing session (organised by bird clubs throughout the country). Or go to a pet shop and stare at the budgies for a while. These days, digital photos are of such high quality that it is easy to distinguish different types feathers. Before long you will be able to instantly distinguish the different feather groups on any bird you see in the field. Pay particular attention to the complex arrangement of the wing feathers, noting how the outer feathers slide beneath the inner feathers as the wing closes. The same principle applies to the tail feathers.
Just like a mechanic needs to know the different engine parts in a car, and what their respective functions are, so a birder must be intimately familiar with bird “topography”. You wouldn’t trust a mechanic who claims he has to fix “that square, metal, boxy-type thing”…likewise, you will understand what you observe, and be able to communicate this much better once you’re confident with all the parts of a bird.
So before I desecrated this poor little canary, I made a video where I briefly run through the main body parts and feather tracts and their functions. I did this by taping my phone to a tripod handle and building a little studio in my office. Afterwards I painstakingly plucked out each feather of the bird. I was terrified of an unexpected sneeze, especially with all the dust and fine particles floating around! I also scanned some of the feathers…check it out below.
One thousand, six hundred and eighty-nine feathers. The vast majority of these are just contour feathers lining the body: the breast, belly, flanks, rump, mantle/scapulars, neck and head. In fact, the prominent tail and flight feathers together make up only 2,5% of the total number. In terms of the body feathers, what we see when we look at the bird is really only the tips of the feathers. As you can see in the video each feather has an extensive blackish grey base with a tangle of soft fluffy that aids in thermoregulation.
I found it virtually impossible to count the tiny feathers on the head and face individually so I worked with a guesstimate of 300. Likewise, the tiny lesser coverts and marginal coverts around the carpal region of the wing proved very difficult to count, especially on such a small bird. Ditto for the feathers on the thighs. Nevertheless, my approximate total fits quite nicely in the 1,500-2,600 bracket typical of songbirds. It must also be noted that this bird was in active body moult, so there were a few tiny feathers just emerging from the skin.
It was fascinating to note the difference in shape between feathers on different parts of the body. For example, the breast feathers are realtively short whereas those on the flanks are much longer (often reflected in spots on the chest, but long streaks on the flanks in many birds). The undertail coverts – and especially the most distal ones – are also very long. The black-tipped throat feathers are only about 3 mm long, whereas the longest primary was around 70 mm in length. The rump area seemed particularly densely feathered.
So now we know.
- Breast and belly feathers: 303
- Flank feathers: 250
- Throat feathers: 63
- Undertail coverts: 25
- Uppertail coverts: 12
- Mantle feathers and scapulars: 165
- Head and face feathers: 300 (approximately)
- Rump feathers: 127
- Thighs / tibia feathers: 40 x 2 (approximately)
- Underwing coverts and axillaries: 48 x 2
- Coverts and alulas: 110 x 2 (for each wing)
- Flight feathers: 18 (x 2, for each wing)
- Tail feathers: 10 (+ 2 in moult)