rmura@world.std.com (Ron Mura) (10/03/90)
While at the Red Sox game last evening, around 8:15, I noticed I bird flying above the field. It appeared to be a warbler and confused by the banks of bright lights. It flew around for a few minutes in erratic directions at about the level of the lights, sometimes higher and sometimes lower. It finally flew above and beyond the lights in a northerly direction and out of sight. I wondered if this bird could have been navigating by the full moon and become confused by the lights. Is this a likely explanation? Is it a common occurrence? -- - Ron Mura, Boston, Mass. rmura@world.std.com
JAHAYES@MIAMIU.BITNET (10/04/90)
WARNING: THIS FOLLOWUP HAS NOTHING TO DO WITH BIRDS. BUT IT'S A
NEAT STORY, ANYWAY....AND TURTLES ARE AT LEAST VERTEBRATES....
It turns out that one of the really large sources of mortality
for hatchling sea turtles is baseball parks in the baseball-crazy
central american countries. There are at least two known turtle
beaches that had ballparks built up top of the dunes, now when
there's a hatch and a night game at the same time, the turtles
head for the brightest spot on the horizon, which is (natch) the
ballpark. Archie Carr tells a wonderful story (told, I mean; he's
gone now) about such an occurrence in Guatemala, where in the
middle of the game this torrent of little green floppy guys came
in from the right field fence....all the campesinos grabbed them
and ran off to the ocean with them. It's a nice story.
So the point is, bright lights can certainly disorient animals
trying to get oriented....well, I'm done now...
P.S. I actually got a lifer warbler in this fall's migration!
A well-colored male Canada. Also a "second-time-in-my-lifer",
a cooperative male black-throated green. Whee.
Josh Hayes, Zoology Department, Miami University, Oxford OH 45056
voice: 513-529-1679 fax: 513-529-6900
jahayes@miamiu.bitnet, or jahayes@miamiu.acs.muohio.edu
Now look inside; what do you see? That's easy: that's a pickle.horvath@granite.cr.bull.com (John Horvath) (10/05/90)
It sounds like you described the situation pretty well, except that
the full moon probably had little to do with. I saw one PBS show that
was discussing bird migration. They mentioned that early Radar
engineers use to believe that there was some sort of fall weather
phenomenon that happened at dusk that would cause extraneous beeps
on their radar screens. Eventually they discovered that it was large
groups of passerines that were apparently waiting in trees until
dark and then flew up and over the tree tops on their migration.
With the full moon the past few days, I was thinking about the
possibilities of being able to see migrants at night passing in front
of the moon. Especially after an incident 2 days ago when something
thumped into the side of our house just before midnight. I'm pretty
sure it was a wayward migrant too.
I've heard that one common trap to migrants is flying into radio
towers. The person who told me the story, claimed that the collisions
were more frequent on foggy nights. I've tried to verify this story,
but all the radio towers I could find, are enclosed in fenced in
areas. ("Yes officer, I was just looking for some dead birds.")
Speaking of migration collisions, in a local book put out by the
BBC (Brookline Bird Club) a few years ago, there was an interesting
article detailing the smashed species that were found around the base of the
Pruditial Tower in Boston.rmura@world.std.com (Ron Mura) (10/05/90)
In article <1990Oct4.172011.1686@granite.cr.bull.com> horvath@granite.cr.bull.com (John Horvath) writes: > > was discussing bird migration. They mentioned that early Radar > engineers use to believe that there was some sort of fall weather > phenomenon that happened at dusk that would cause extraneous beeps > on their radar screens. Eventually they discovered that it was large > groups of passerines that were apparently waiting in trees until > dark and then flew up and over the tree tops on their migration. A few months ago, there was an article in the paper about a scientist who had access to photos of these radar screens going back 25 years, and he was using them to demonstrate the dramatic drop-off in migrating birds over that period of time. > With the full moon the past few days, I was thinking about the > possibilities of being able to see migrants at night passing in front > of the moon. I've known birders who do that, and also listen and can identify migrants by call. One locally famous and well respected birder (he's high up in the Mass. Fish and Wildlife dept.) recorded 400 migrating blue-gray gnatcatchers one night in Wellesley, Mass., in the 1960s. The same fellow can supposedly identify birds flying in front on the full moon through his scope. > Speaking of migration collisions, in a local book put out by the > BBC (Brookline Bird Club) a few years ago, there was an interesting > article detailing the smashed species that were found around the base of the > Pruditial Tower in Boston. I work at John Hancock in Boston, which has a 60-story tower. One spring morning I found a dead scarlet tanager at the foot of the building, which was very sad. (I don't work in that building normally.) I've heard that it is fairly common in spring anyway (don't know about fall) to find dead birds in the morning. Ron -- - Ron Mura, Boston, Mass. rmura@world.std.com
andrewt@cs.su.oz (Andrew Taylor) (10/06/90)
In article <1990Oct4.172011.1686@granite.cr.bull.com> horvath@granite.cr.bull.com (John Horvath) writes: >It sounds like you described the situation pretty well, except that >the full moon probably had little to do with it. I'm not so sure, the most plausible explanation seems that the birds confused the lights for the moon. Ceilometers, intense vertical searchlights used to measure the height of clouds at airports, used to take a huge toll of migrating US birds. The worst being 50,000 of 53 species in one night. The birds fly into the ground which is consistent with them assuming the searchlight is the moon. >I've heard that one common trap to migrants is flying into radio >towers. The person who told me the story, claimed that the collisions >were more frequent on foggy nights. This is true, and unfortunately weather condusive to migration will often be that likely to produce fog and overcast. In one of the worst incidents 30,000 were killed in two nights by one radio tower. You'd think some form hazard beacons could be installed on the these towers to warn birds maybe tape loops of raptor calls would work. Andrew
misan@ra.abo.fi (Annika Forsten DC) (10/10/90)
In article <RMURA.90Oct4212434@world.std.com> rmura@world.std.com (Ron Mura) writes: > > was discussing bird migration. They mentioned that early Radar > > engineers use to believe that there was some sort of fall weather > > phenomenon that happened at dusk that would cause extraneous beeps > > on their radar screens. Eventually they discovered that it was large > > groups of passerines that were apparently waiting in trees until > > dark and then flew up and over the tree tops on their migration. > > With the full moon the past few days, I was thinking about the > > possibilities of being able to see migrants at night passing in front > > of the moon. > I've known birders who do that, and also listen and can identify > migrants by call. One locally famous and well respected birder > (he's high up in the Mass. Fish and Wildlife dept.) recorded 400 > migrating blue-gray gnatcatchers one night in Wellesley, Mass., in the > 1960s. The same fellow can supposedly identify birds flying in front > on the full moon through his scope. > > Speaking of migration collisions, in a local book put out by the > > BBC (Brookline Bird Club) a few years ago, there was an interesting > > article detailing the smashed species that were found around the base of the > > Pruditial Tower in Boston. I missed the first part of this discussion so I'm sorry if I'm repeating something somebody else already said. I suppose any high towers with light act as birdcollectors during foggy or otherwise bad weather. I've spent a few nights in a lighthouse watching birds migrate. I haven't been up there on a really foggy night, but even on a half bad night lots of birds collided with the lighthouse. It's really intresting to see them go by and hear them calling. As said it is quite possible to try counting them. Identifying them against the moon is more difficult I'd say. Easy with some species, but I'm quite sure not all passerines could be identified on silhuette alone. I've heard stories about how they found thousands of dead birds under a lighthouse after a foggy night, including several rarities. I don't quite understand why they fly up to the lighthouse though, after all they don't try flying all the way to the moon. On one night there was a Short-eared Owl flying around the lighthouse. Catching the birds that flew by? Opportunist? Annika Forsten, Finland
deby@cs.utwente.nl (Rolf de By) (10/13/90)
In article <1990Oct4.172011.1686@granite.cr.bull.com> horvath@granite.cr.bull.com (John Horvath) writes: > I've heard that one common trap to migrants is flying into radio > towers. The person who told me the story, claimed that the collisions > were more frequent on foggy nights. I've tried to verify this story, > but all the radio towers I could find, are enclosed in fenced in > areas. ("Yes officer, I was just looking for some dead birds.") Here in Europe (and especially in Denmark and Holland) one of the main causes of death of migrating birds used to be lighthouses, and indeed, mostly so during foggy nights in autumn. Apparently, in such nights the birds start circling around the single light source that they can find and eventually hit the walls somewhere. The number of casualties has seen a dramatic decline from the moment the lighthouses were put in footlights, so that now the birds could see the whole building and not just its head. On the same issue rmura@world.std.com (Ron Mura) wrote: > I've known birders who do that, and also listen and can identify > migrants by call. One locally famous and well respected birder > (he's high up in the Mass. Fish and Wildlife dept.) recorded 400 > migrating blue-gray gnatcatchers one night in Wellesley, Mass., in the > 1960s. The same fellow can supposedly identify birds flying in front > on the full moon through his scope. Sure, you can identify birds by their call, that is IF they call during migration. Some species do, others don't. The Redwing (a eurasian thrush that, I believe, is in the Nat. Geogr. guide) calls all the time, and you can hear at least several hundreds during the night wherever you are; the Fieldfare (a thrush also in that guide?) hardly ever calls during the night. I think not that many small passerines give contact calls when migrating at night, and so I would be surprised if the Gnatcatcher does. Does it? Identifying birds flying in front of the full moon through your scope is ridiculous, I believe. OK, Cranes are allright, and so are Canada Geese. But forget about all the smaller species. Either they passed too quickly because they were too close, or they are too far anyway. If you believe this guy could identify any of the parulidae in this fashion, . . . Rolf Rolf A. de By Vakgroep Informatiesystemen Tel : (0)53--893753 Faculteit der Informatica b.g.g.: (0)53--893690 Universiteit Twente Fax : (0)53--339605 Postbus 217, 7500 AE Enschede Email : deby@cs.utwente.nl The Netherlands deby@henut5.bitnet