[Tweeters] Case not closed on Barn Swallow series

Bob and Barb Boekelheide bboek at olympus.net
Tue Nov 4 23:49:08 PST 2008


Hello, Dennis, Ed, Devorah, and tweeters,

Your swallow photos and commentary remind me of an episode we
witnessed at the Farallon Islands in California many years back. One
of our known color-banded male Pigeon Guillemots died face down on
some rocks where we could watch its carcass. After awhile another
known color-banded male guillemot came over to the dead bird's
carcass and began courting it, strutting all around the carcass, then
mounting and copulating with the dead bird. Other than us making a
few off-hand remarks about perverted California alcids, we wrote it
off to uncontrollable hormones, certainly not necrophilia.

A few times we also witnessed male northern elephant seals attempting
copulation with dead elephant seals, even ones that had been
decomposing on land for a few days. Once a big subadult male seal
got amorous with a decomposing carcass, started to mount it, then
slammed his weight down on it like male elephant seals do to subdue
females when mating, causing a big bunch of putrid gas blisters to
burst. PU-EEEEE -- what a surprise! Of course elephant seals are
not your most intelligent animals, but it's not just birds that make
these counter-intuitive mistakes while trying to mate.

Like you say, the urge to reproduce can be overwhelming.

Bob Boekelheide
Sequim
bboek at olympus.net



From: Dennis Paulson <dennispaulson at comcast.net>
Date: November 3, 2008 1:07:51 PM PST
To: tweeters at u.washington.edu
Subject: Re: [Tweeters] Case not closed on Barn Swallow series

Hello, tweets.

I usually stay out of these controversies, but Ed's post prompted me
to look at the photos that Devorah posted. From everything I know
about birds, I would agree with Chris Hill's message, in which he
stated that the live bird was almost surely trying to mate with the
dying/dead bird. I came to these conclusions before reading his post.
I don't see how any of the photos can be interpreted as a grieving
bird. Swallows very often copulate on the ground, and I have several
times seen a male Barn Swallow swoop down and land on a female
perched on the ground and copulate with her - don't know whether they
were mates or not.

The reason Cliff Swallows always hold their wings up when gathering
mud on the ground is to repel males that try to copulate with them.
Experiments have shown that any bird with its wings down is the
target for such attempts. At swallow colonies (several species), you
see two birds flying together all the time because if the male
doesn't follow right on the tail of his mate, another male will
attempt to mate with her, and she will let him.

I think necrophilia is a quite inappropriate term to apply to this.
In beginning animal behavior classes, you would learn that male
European Robins will attempt to mate with a bunch of robin-colored
feathers on the ground. The mating urge is a strong one, and in
nature the more an animal mates, the more genes it passes on to the
next generation. Natural selection has been very direct and intense
on the drive to mate. I doubt if any animal would attempt to mate
with another individual that it "knew" was dead, and I suspect that
judging death and what it means may be difficult for most animals.

The "scientific case" made by both Chris and me is that everything we
can see in these photos matches what we already know about bird
behavior, swallow behavior, and Barn Swallow behavior, whereas we
have no empirical evidence for "grieving" in swallows; and I don't
think they feed their mates even when healthy (unlike many other bird
groups, in which courtship feeding occurs). That is not to say that
birds aren't affected emotionally when their mates die, but these
emotions seem to be more likely in birds that mate for life - like
ravens and swans and parrots - and not so likely in birds that mate
anew each breeding season - like swallows. Studies on these birds
have usually shown them to attempt to find a new mate very quickly if
their present mate dies or disappears.

I'm not saying birds don't/can't show grief, but I think we should be
just as critical in attributing "grief" as we are in attributing "no
grief." We are a very social species, with long friendships and
intense family ties, and it would be a mistake, I think, to attribute
human emotions to birds that live only a few years, mate with a new
mate every year, dump that mate with no hesitation if there is
anything wrong with its abilities, abandon their young soon after
they fledge, never to have anything to do with them again unless they
attempt to mate with them in the following year, and show no sign of
having "friends" in the way we think of that term.

Male Barn Swallows at colonies routinely kill chicks of mated pairs
and then attempt to mate with the female of the broken-up pair. The
females often accept them. Should we judge these birds by human
emotions?

Dennis Paulson

On Nov 3, 2008, at 12:01 PM, tweeters-
request at mailman2.u.washington.edu wrote:
Date: Sun, 2 Nov 2008 23:40:39 -0800 (PST)
From: Ed Newbold <ednewbold1 at yahoo.com>
Subject: [Tweeters] Case not closed on Barn Swallow series
To: tweeters at u.washington.edu
Message-ID: <134497.10578.qm at web35201.mail.mud.yahoo.com>
Content-Type: text/plain; charset="windows-1252"

Hi all,

I wish to point out that there has been no truly persuasive case made
that the Barn Swallows in the set of pictures that Devorah kindly
linked to--


http://scienceblogs.com/grrlscientist/2008/10/
one_of_lifes_tiny_dramas.php

was certainly a case of necrophilia or the taking advantage of a
dying swallow by another—and/or that it had absolutely no component
of grieving or something like it.


You don’t need to be a credentialed scientist to realize that more is
needed to be known about the specific birds in the picture, and more
about the sequence in question and perhaps more about Barn Swallow
behavior to arrive at a certain conclusion as to actually what is
going on in those pictures. Some scientific humility is clearly
called for.

The need to make a truly scientific case cuts both ways, not only to
people proposing so-called “anthropomorphic” interpretations of
events but also to those who would categorically rule them out as
explanations.

Thanks again to Devorah.

Ed Newbold ednewbold1 at yahoo.com Beacon Hill Seattle

-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net

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