Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!ub!acsu.buffalo.edu
From: dmark@acsu.buffalo.edu (David Mark)
Newsgroups: rec.birds
Subject: Re: Wintering in the Summertime
Message-ID: <79080@eerie.acsu.Buffalo.EDU>
Date: 6 Jun 91 11:25:29 GMT
References: <Jun.5.09.00.22.1991.9090@remus.rutgers.edu>
Sender: news@acsu.Buffalo.EDU
Organization: SUNY Buffalo
Lines: 38
Nntp-Posting-Host: autarch.acsu.buffalo.edu

In article <Jun.5.09.00.22.1991.9090@remus.rutgers.edu> jclarke@remus.rutgers.edu (James C. Clarke) writes:
>
>	I hope that this is the right forum for this question.  There are a 
  great number of birds in North America that winter in South America, some as 
  far as Argentina.  Now, I suppose that these birds are "wintering" in a 
  locale that is then in it's summer. I
> would also assume that these birds are non_breeding and interact with local 
  bird population which is breeding.  With the exception of a few pelagic 
  species, such as a several species of Albatross, are they any species of bird 
  that the main portion o
>species "winters" in the Northern Hemisphere's summer?  I can't think of any. 

I can't think of any, either.  There are other southern-breeding seabirds
that are here in our summer (their winter), such as most shearwaters and
storm-petrels.  But no land birds that I know of.  But it is not surprising,
I think.

Almost all latitudinal migrants breed in the temperate or arctic zones.
Tropical breeders tend to be sedentary, or altitudinal migrants.  The temperate
land area in the southern hemisphere is rather small.  For example, Uruguay
is the only South American country that has no part in the 'tropics'
(between 23-23 N and 23-23 South).  Similar small temperate areas in
Africa and Australia.

Next, relatively few of our breedings birds go all the way through to the
temperate zone or antarctic zone.  The only land birds I can think
of right now that do that are some of the swallows.  Others would be many
shorebirds and seabirds.  Most of our migrants stop in the tropics, or north 
of the tropics.

So, on hand-waving probability alone, it is not surprising that transtropical
migrants that are southern breeding landbirds are uncommon or absent from the 
planet. (In Australia, only a dozen or so land birds leave the country entirely 
in winter (Dollarbird, several cuckoos), and they do not regularly go beyond the
tropics.)

David Mark
dmark@acsu.buffalo.edu