Jon:
Great observation. I have recently learned that birds flying over water
usually do so at a much lower altitude than when they fly over land. Any
ideas why? What was the wind conditions? It makes sense that most birds
would lose elongated tails when flying over long-distances. Doing so, would
reduce the bird's aerodynamic drag ... your observation also supports the
notion that elongated tails have evolved because of sexual selection, and
helps pin down migration dates of bee-eaters that are bound to vary from
year to year. Thanks for sharing your observations. May I post your
observations on "ibirding"?
Cheers, Jim
Dr Wm James Davis, Editor
Interpretive Birding Bulletin
Trial copies of the Bulletin and
book reviews are available online
www.ibirding.com
> Gooday Frank and birding-ausser's,
> I have also been observing the flocks of Rainbow Bee-eaters passing
through
> the Torres Strait Qld. over recent weeks.
> The majority of birds were either juveniles or adults that had lost their
> elongated tail feathers. Only a few adult birds were observed over a four
> week period. Size of flocks varied from 10 birds up to 50 birds with two
> flocks observed in early April of 100+.
> When travelling over land they remain quite high, but over sea they are
> within a couple of metres of the surface usually giving their
interpretation
> of the Roadrunner "breep, breep, breep"
>
> Jon Wren
>
> Birding-Aus is on the Web at
> www.shc.melb.catholic.edu.au/home/birding/index.html
> To unsubscribe from this mailing list, send the message
> "unsubscribe birding-aus" (no quotes, no Subject line)
> to
>
>
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
To unsubscribe from this mailing list, send the message
"unsubscribe birding-aus" (no quotes, no Subject line)
to
|
