Tetrapod Zoology

Regular readers might remember the ‘pigeon in the fireplace’ incident of March 2007, when a Wood pigeon Columba palumbus fell down my chimney during the small hours of the morning and had to be extricated at great personal cost to my epidermis. As I grabbed the pigeon, I was slightly dismayed that its entire rectricial array (viz, all of its tail feathers) came out in one clean, bloodless mass. The word on the street is that pigeons have very shallowly rooted rectrices and can effectively ‘drop’ the tail when grabbed by a predator, which is pretty neat I think you’ll agree.

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So far as I can tell this is unique to pigeons. I’ve occasionally had to grab or restrain other birds by holding or pulling their rectrices (particularly budgies), and those feathers have always been well-rooted enough to prevent the escape of the bird. So it’s tempting to think that pigeons have ‘autotomic’ rectrices, convergently similar to the autotomic tails of some lizards, some mice, and some salamanders.

By bizarre and curious coincidence, I have recently been finding bits of evidence in the field that vindicate this idea (and by ‘finding bits of evidence in the field’ I mean ‘things I have stumbled upon while gallivanting about on various thrilling adventures’)…

Exhibit A is the dead Wood pigeon I encountered on the way to Southampton train station in August [shown above: that's the pose I found it in]. I initially walked past the bird and hurried on – after all, dead Wood pigeons aren’t quite enough to get me excited – but after a few minutes I knew I’d regret not photographing it, so I walked all the way back to where it was (partly this was to look at the ventral surfaces of the claws. I do a lot of that these days. You know why). To my mild surprise it was lacking rectrices entirely: it appears that the entire rectricial array had come cleanly away. I have no idea why it died, but it wasn’t far from the road and might have been hit by a vehicle (wood pigeons are good at this).

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Exhibit B [shown here] was encountered today as Will and I walked home from school. A detached retricial array of a Wood pigeon (keys for scale). I cannot recall ever seeing a clump of retrices (of any bird) just lying on the pavement like this, and I infer that the entire tail array was dropped when, again, the bird underwent some sort of traumatic experience. If you’re wondering, yes these are definitely rectrices and not remiges based on their shape (squared-off ends) and distinctive three-shade banding.

If I didn’t already know that pigeons can do an emergency drop of their tail feathers, I doubt if I’ve had found these two discoveries interesting. But I do, so I did, and thought it worth telling you. Finally, back in May 2007 I wondered whether the pigeon I rescued would survive its ordeal. People told me that pigeons are tough and recover quickly from stress. Well, in the weeks that followed the rescue I saw what I assume was the same pigeon: a week after the rescue it had no rectrices. A few weeks later it had short ones, and so on and so forth. Of course, it might have been another pigeon that looked just like the one I rescued. There are a lot of them around and they’re not easy to tell apart. But never let the facts get in the way of a good story.

Hmm. I should write a regular column, like Carrie does in Sex and the City. Oh, maybe I already do.

Next… flightless pterosaurs!

Comments

#1 Zach Miller
September 18, 2008

Please, please never EVER mention that show on this blog again. It’s a science blog. About science. Not four vaguely unattractive, narcisistic women who have way too much sex and claim to be strong independant members of society when all they ever talk about is troubles with the opposite sex.*

In other news, that’s awesome about pigeons! I can see how such a feature would be advantageous in a bird that routinely lives in populated areas infested with cats, dogs, and small children.

*My response to this particular HBO show is gutteral. My wife has the entire series on DVD and has watched it several times through. She will also watch it if it happens to be on TV. The show has infiltrated basic cable stations now, so there’s no escaping it. I don’t think I’ve ever hated, with such passion, four fictional characters in my entire life.
#2 Erin
September 18, 2008

Stumbled through, fascinating article! I like your writing style a great deal. Gerbils and geckos (and some other reptiles) do very much the same thing, but I’m sure you knew that. I wonder if the niches are similar enough in the wild to explain this?

@ Zach. As a woman, I am truly sorry that show is being inflicted on you. I’ve never seen it, but the tidbits I absorb are enough for me to hate it. I actually do like being a strong, independent member of society. Oddly enough, focusing on my own goals and forgoing fashion earned me a loving boyfriend who supports my independence. I’m happy to see men who not only obviously appreciate women, but appreciate them enough to call BS when they see it.
#3 ReBecca
September 18, 2008

Hi Darren. This actually has happened to me before. Well, not to myself, but to one of my cockatiels. It was a younger bird, about a year old and he was out of his cage sitting on the arm of the couch. My sister accidentally put her arm down on his tail and this scared the poor guy, who flew off without any of his tail feathers. They all came out with out any blood and it took the poor guy about 6 months for all of them to grow back. This also happened to result in his failure to remember how to fly and he never “flew” again (he tried, but only would fall – he lived for at least another 10 years and fathered several ‘children’).
#4 Alec T
September 18, 2008

A poster here had a similar situation as yours with a pigeon in the chimney, and it’s tail feathers came right off:

http://forum.pigeonbasics.com/m-1215545610/

Didn’t say what species, though
#5 John Scanlon FCD
September 18, 2008

Given their near-constant use in social display, autotomy of rectrices in pigeons seems a bit surprising; I’d expect that losing the tail is social near-death. (Testable hypothesis)
My intuition on this is formed by observations on several species of skinks (Lampropholis and Carlia spp.) that practice tail-waving as a social and predator-detection signal. I used to catch a lot of Lampropholis guichenoti from several different localities (small elapids think they’re yummy), and noticed that some individuals were strong tail-wavers, others not, with frequency varying between localities (unpublished… now where did I put the original data?). I also found that tail-wavers were unlikely to have broken or regenerated tails, and vice versa. AND, a skink suspended by its tail tip would usually readily autotomise UNLESS it was a tail-waver, in which case they would hang from the tip of the tail, wriggling madly, for at least several seconds. OK, I never did the stats but I think that was a real difference. Conclusion: Loss (at least temporarily) of signalling function may be a significant cost of autotomy.
On the other hand, maybe previously evolved autotomy actually favoured use of the tail as a signal in pigeons, as it certainly has in lizards. When tail loss is common, flaunting an original tail is an honest signal of quality that can be read by conspecifics and predators.
#6 redstart
September 19, 2008

This reminds me of a paper published in J Avian Biol (or in its precursor, Ornis Scandinavica) about the ‘cloud’ of (contour) feathers gettin away from birds trapped for ringing when they are liberated (or when, e.g., a falcon attacks a flock of starlings). Authors named their speculation ‘Birds doing the octopus way’, arguing it could be a tactic to confuss predators.
#7 Sordes
September 19, 2008

I wonder if this can be found also in other birds. I think I have already seen suspiciously many adult blackbirds with lacking tailfeathers. Given the fact that they spend a lot of time on the ground where they are especially endangered by cats and other small carnivores, such a trick would make much sense for them.
#8 William Miller
September 19, 2008

I wonder if Rock Pigeons (is Columba livia given a different scientific name in Britain?) do the same thing?

And … flightless pterosaurs? I thought you had mentioned in the past that none were known…
#9 Neil
September 19, 2008

I have to firstly echo Zachs request not to mention THAT show, the best description of which come from Brian in Family Guy “Its a show about 43 hookers and their mum!?”

On to pigeons loosing their tails, I had no idea they could do this. Ive seen something similar to the second image quite a few times and just thought it was what was left of an eaten pigeon. Fascinating stuff
#10 Jerzy
September 19, 2008

Pigeons have generally thin skin for a bird. Maybe it’s the reason? I read that taxidermists hate pigeons and trogons, but like parrots, raptors and woodpeckers for that reason.

BTW, over the years I saw many birds minus tail. Magpies and thrushes, for example.
#11 Neil
September 19, 2008

my above post should say 3 not 43
#12 Tom
September 19, 2008

“So far as I can tell this is unique to pigeons.”

I can confirm that cockatiels do lose their tail feathers after our toddler son slammed our cockatiel’s tail in a door. The bird was about 10 years old at the time. It took about five months for him to regrow his tail feathers. During this period he continued to fly around the house but without as fine control as he had before. After his new tail feathers grew out completely, he was able to fly just as well as ever.

We used to have many feral cats in the neighborhood. I’ve seen goldfinches, sparrows, robins, turtledoves and starlings in the back yard who were missing their tail feathers but who were otherwise quite healthy and mobile.
#13 Darren Naish
September 19, 2008

Thanks to all for comments. Don’t get me wrong – all birds with rectrices can lose them when those feathers get yanked at, shut in a door, or trapped… I’m saying that it might only be pigeons that can instantly lose the entire tail following even a relatively light touch.

Yes, this might be costly as goes sexual display and aerodynamics, but the bird still gets to live and – anyway – it can still peform aerodynamically (and probably sexually) without the tail.
#14 Shawn
September 19, 2008

While trying to capture an escaped pet parakeet/budgie/psychotic dive bomber…I pulled out several feathers..no blood, well, not from him anyway. I sustained minor injuries…but he did grow them back, along with the ability to fly and a renewed desire to escape.

THAT show is the epitome of crappy programming. I know many “independant woman” who are more than happy to explain the difference between being “independant” and just being “slutty”.
#15 carel
September 19, 2008

Any falconer can confirm that the rectrices and rump feathers of birds of all kinds are often sacrificed in exchange for an escape from a predator. The calamus tips of pigeons are, as far as I know, unique in their form and attachment. This applies, to some degree, to all of their feathers, which are all easily shed, and can afterwards be identified as belonging to a pigeon by the unusual nozzle-shape of their base.
#16 Lee Ann
September 19, 2008

Once, I had to rescue a hummingbird from my living room window, and came away with a few teensy hummingburd tail feathers. Miraculous!
#17 Corvid
September 19, 2008

Hi Darren – long-time lurker, first-time commenter here. I am currently working at a bird banding station (you’d call it a bird ringing station) in western Canada, and I can tell you from experience that many bird species can lose their rectrices quite easily, especially when they are stressed. Spotted Towhees (Pipilo maculatus), Song Sparrows (Melospiza melodia), some wrens, and most juveniles seem particularly prone to losing their rects easily. When ageing and sexing birds, I have to be careful when looking at the rects: sometimes juveniles/hatch-years lose them to predators, and then grow in a more advanced generation of tail feathers, making them look older than they actually are! In fact, just this morning I had a hatch-year Lincoln’s Sparrow (Melospiza lincolnii0 with an out-of-place, adult tail. I would be interested to know which groups of birds in particular are more prone to tail-loss, and what kind of structural differences are involved.
#18 Darren Naish
September 19, 2008

Ok, thanks for that, and thanks everyone – I’ve learnt a lot from your comments.
#19 Heather
September 19, 2008

I have in fact seen feathers on the ground like your second photo, but the idea that they detached like that never occurred to me. How interesting!
#20 jason
September 20, 2008

hmmm…dont jump to conclusions tho, could be a number of things that makes this appear as so. For example just reading these comments i thought what about the birds diet in the environment they are in…could thier diet cause this strange thing to happen, weak tail feathers?

could be worth a study tho;)
#21 Tommy Tyrberg
September 29, 2008

A very late comment, due to having been away for a while. Many (most?) birds have the ability to lose feathers suddenly when stressed. There is even a word for it in Swedish: “skr�ckruggning” (literally Terror Moulting). It is phylogenetically very widespread, including galloanseres, so it may well be primitive for Neornithes.
#22 melvin
February 11, 2010

I found a rock dove, and I’m nursing it. It’s about 2-3 weeks that I have it, but it’s been 2 days that I found blood under it. what it going on??? is s/he sick?? or just ready to lay eggs? plz answer my question, that bird it’s really important 2 me!
#23 jack wooldridge
September 23, 2010

I keep racing pigeons and their feathers would require a good yank to come out, but I also have had Bandtails, a wild pigeon, and they seemed to easily cast off feathers in my grasp. Being wild, the probably were quicker to evoke an escape behavior.