An apparent case of fright-moult (autotomy of feathers) in the laughing dove (Spilopelia senegalensis)

@felix_riegel @tonyrebelo @jeremygilmore @baldcoot @aguilita @ldacosta @jimsinclair @lsueza @adamwelz @colin25 @karimhaddad @lukedowney @thebeachcomber @botswanabugs

Autotomy (https://en.wikipedia.org/wiki/Autotomy) is known in various animals. However, its incidence in birds is poorly-documented.

There are intriguing hints, on the Web, of autotomy of the feathers in small-bodied columbids, viz.

Please see:
https://www.birds-online.de/wp/en/birds-online-english/health-and-diseases/plumage-disorders-and-molt/moult/fright-moult/ and https://www.sarveywildlife.org/blog.aspx?post=3023&title=Mourning-Dove-attacked-by-cat and https://feederwatch.org/unusual-bird/mourning-dove-without-tail-feathers/

The term used has been 'fright moult' or 'fright molt'.

Also please see https://www.youtube.com/watch?v=mLJ0m5gEEf0 and https://www.facebook.com/watch/?v=600613034506485 and https://www.birdnote.org/listen/shows/having-your-tail-scared and https://wrenandsparrow.com/blog/f/fright-molt and https://folkwaysnotebook.blogspot.com/2015/08/fight-or-flight.html.

If certain species of birds, particularly Columbidae (https://www.inaturalist.org/observations?place_id=any&taxon_id=2715&view=species), use autotomy of feathers as a way of escaping from predators, this seems analogous to the shedding of tails by lizards when attacked.

I have, at various times in my life, found piles of the feathers of doves, in both the Perth metropolitan area of Western Australia, and in Cape Town, South Africa.

I did not record all these occasions, which may possibly total as many as 20 over my lifetime so far, in which feathers were present in quantity but there was no trace of other body-parts.

I paid too little attention at the start, because I was naive about the possibility of 'fright moult' in birds. I had simply presumed that the feathers were the refuse of a kill, not considering that the bird might instead have escaped.

Once I realised the possibilities, I recorded the following.

On 5 July 2006, in the suburbs of Fremantle, Western Australia, I encountered particular evidence of this kind of autotomy. This was during a spell of calm weather, when there was no wind to remove the feathers.

On the lawn of a wide road-verge, I found what looked like the results of a 'feather-explosion'. I am unsure of the identities involved, but I suspect that the bird was an individual of Spilopelia senegalensis (https://www.inaturalist.org/taxa/1455922-Spilopelia-senegalensis), and the attacker was an individual of Felis catus, pouncing in vain by day, on the ground.

The road-verge here was wide, and the feathers were far (at least 3 m) from the tarmac. This means that the dove was probably not hit by a motor vehicle.

I collected most of the feathers, which totalled about 370 of various types and sizes (from one individual bird). If these feathers were shed on 4 or 5 July 2006, I found them one day after the attack, or on the same day.

The smallest were merely down feathers. The largest, which were >5 cm long, were probably secondaries.

I do not know if the attacker (probably F. catus) caught this dove, but I suspect that it did not.

Were the feathers detached in reaction to pressure exerted by the predator, or shed spontaneously before contact was made? On this occasion, some of the secondaries seemed to be aggregated at their bases, suggesting that they were detached in the clutches of the attacker.

However, the sheer number of feathers indicates that many or most of them were shed without being pulled off in any way by the attacker.

Has any Reader observed any similar evidence of fright-moult, referring to S. senegalensis, G. cuneata, Z. macroura, any other species of columbid, or any other species of bird?

Also please see https://www.inaturalist.org/journal/milewski/68965-the-difference-between-commensalism-and-habituation-exemplified-by-spilopelia-chinensis-in-australian-suburbs#.

Posted on May 21, 2023 12:30 PM by milewski milewski

Comments

Many thanks for your observation and thinking.
Unfortunately, I had not met individuals of this type in this state and I had not thought of what you have just said.
It's a thing that you can still follow in the future to achieve results

Posted by karimhaddad about 1 year ago

@karimhaddad

Dear Karim,

I suspect that the local people, living in villages and oases in the Maghreb (including Algeria), know about the shedding of feathers by Spilopelia senegalensis when attacked by the domestic cat.

I suspect that, if one were to ask around in such places, one might hear the response 'of course that happens', based on common observation by rural people.

In other words, I suspect that this is one of those aspects of the biology of birds which has long been known to non-scientists, but overlooked by ornithologists.

Your further thoughts?

With kind regards from Antoni

Posted by milewski about 1 year ago

I assume this is a kill or attack rather than a fright moult ! very interesting article and we need to keep a look out more carefully. https://www.inaturalist.org/observations/77866063

Posted by botswanabugs about 1 year ago

@milewski what do you make of this observation ? https://www.inaturalist.org/observations/156657380

Posted by botswanabugs about 1 year ago

Please scroll to the section headed 'Feathers', for a mention of fright-moult:

https://www.discovermagazine.com/planet-earth/pigeons

Posted by milewski about 1 year ago

The following (https://theparrotsocietyuk.org/site/index.php/parrot-information/veterinary-advice/feathers/moulting/) states "attack or accident: there are some species like pigeons and touracos that can shed their feather (sic) easily in such a situation, leaving the predator or handler with a mass of feathers, while the bird makes its escape. Such loss is known as 'stress moult', or 'flight loss'."

Posted by milewski about 1 year ago

THE FOLLOWING IS BY FAR THE BEST DESCRIPTION OF FRIGHT-MOULT THAT I HAVE FOUND ON THE WEB: https://besgroup.org/2011/09/02/feeding-spotted-dove-19-an-explosion-of-feathers/

It refers specifically to the columbid Spilopelia chinensis.

In this website, written in 2011, Y C Wee and Lee Chiu San state "I try as far as possible not to handle doves because they shed feathers like snowstorms".

Posted by milewski about 1 year ago

The following is thought-provoking (https://lafeber.com/pet-birds/questions/night-fright-in-birds/).

It leads me to suspect that fright-moult in columbids has evolved mainly for deployment at night.

Columbids have extremely powerful flight. They are capable of such acceleration when attacked by day that it seems unlikely that another extreme anti-predator adaptation (i.e. autotomy) would have benefits exceeding its costs, in the context of well-illuminated situations.

However, at night, diurnal birds such as columbids are likely to be correspondingly vulnerable. Their eyes see poorly in the dark, and explosive flight brings an excessive risk of collisions.

Thus, the two specialisations would complement each other, in a coherent overall anti-predator strategy: extremely powerful acceleration by day, and extreme autotomy by night, in which the instantaneously shed feathers include not just the tail feathers but also many contour and down feathers on the body.

Posted by milewski about 1 year ago

The following (https://meridian.allenpress.com/wjo/article-abstract/132/2/476/459596/Hail-induced-nest-mortality-and-possible-fright?redirectedFrom=fulltext) reports a case of fright-moult in Curruca curruca (https://www.inaturalist.org/taxa/1289484-Curruca-curruca). It suggests that this shedding of feathers in the nest was triggered by the stress brought by a hailstorm.

Posted by milewski about 1 year ago

@botswanabugs

Many thanks for your contributions.

I agree that https://www.inaturalist.org/observations/151731303 and https://pij-n-angels.forumotion.net/t2478-a-pigeon-without-tail are probably cases of fright-moult.

Posted by milewski about 1 year ago

@milewski
perhaps there could be an iNaturalist project dedicated to fright moulting, in which observations of tailless birds and piles of tail feathers are collected together.
Red Cardinal
https://wrenandsparrow.com/blog/f/fright-molt

Posted by botswanabugs about 1 year ago

@milewski
perhaps there could be an iNaturalist project dedicated to fright moulting, in which observations of tailless birds and piles of tail feathers are collected together.
Red Cardinal
https://wrenandsparrow.com/blog/f/fright-molt

Posted by botswanabugs about 1 year ago

Another reason why I suspect that, in columbids, fright-moult is particularly valuable at night:

Various birds, including columbids (https://www.sciencedirect.com/science/article/abs/pii/S0306456501000328 and https://academic.oup.com/condor/article/104/4/705/5563138), allow a decrease in body temperature during sleep, in the interests of conserving energy.

This would particularly limit any ability to accelerate immediately in evasive flight, if the birds are attacked at night.

Posted by milewski about 1 year ago

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