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From: sandee@sun13.scri.fsu.edu (Daan Sandee)
Newsgroups: rec.birds
Subject: Re: Hitch-hiking migrants
Keywords: Hummingbirds
Message-ID: <358@sun13.scri.fsu.edu>
Date: 5 Aug 90 22:15:41 GMT
References: <510@safn2.UUCP> <353@sun13.scri.fsu.edu>
Organization: SCRI, Florida State University
Lines: 32

In article <353@sun13.scri.fsu.edu> I wrote :
>In article <510@safn2.UUCP> jbm@safn2.UUCP (John McClatchey) writes:
>> ...  It does seem very difficult to
>>figure out how a hummingbird could travel across the
>>Gulf without eating, since it has such a rapid
>>metabolism.  I would think it might "run out of gas".
>
>While many warblers cross the Gulf non-stop (some even may fly non-stop
>from Maine to South America, over the Atlantic), the ruby-throated 
>hummingbird mostly island-hops. (All other North American hummingbirds
>migrate by land). And apparently it can stock up enough energy to make it.
 
That was just me pretending to know what I was talking about. Here's the
scoop from the scientific world :

Long-haul migrant store extra body fat before taking off. This has long been
known by comparing the body weight of the fat birds on the taking-off side
with that of the emaciated birds that make it. Odum et al. measured body
weights of various southward bound migrants in Florida, and found that
Ruby-throated Hummingbird may increase its body weight by as much as 100%
(from 2.1 grams to a heavyweight 4 grams). With a rough estimate of the
physiological requirements of level flight, they arrive at a range of 2450 km
(1500 miles).  Thus the 600 miles across the Gulf of Mexico can be covered
easily.
Odum,E.L.,C.E.Connell,H.L.Stoddard, "Flight Energy and Estimated Flight Ranges
of some Migratory Birds", Auk 78:515-527 (1961).
See also,
Lasiewski,R.C.,"The Energetics of Migratory Hummingbirds", Condor 64:324 (1962).

Daan Sandee                                           sandee@sun16.scri.fsu.edu
Supercomputer Computations Research Institute
Florida State University, Tallahassee, FL 32306-4052  (904) 644-7045