Re: Fall migration?

[steven.shultz@unifi.com]

The term fall migration can seem somewhat confusing when applied to bird
movements in the middle of the seasonal summer.  Maybe post-breeding
migration would be better, but then again different species breed at
different times throughout the year.  Anyway, the term fall migration
refers to the generally southward movement of birds that moved north to
breed.  In some species, notably some shorebirds and even a few warblers
like the Louisiana Waterthrush, fall migration is all but over by the end
of August.  In many shorebird species the adults leave the breeding areas
as soon as their young are self sufficient.  This can occur as early as
late June, and in fact the first southbound migrants are often reported
from northern areas at this time.  Most of the shorebirds seen earlier in
the fall movement are adults.  The first year birds follow along weeks
later.  There are various theories as to why this occurs, one being that
the adults leave to secure prime wintering locations at overwintering sites
thus allowing the young birds to remain in the relatively food rich arctic
areas to gain the sustenance needed to make the southward journey.

So basically, fall migration lasts from about July to November.  The
shorebirds usually kick things off around the end of June, warblers and
passerines move a bit later, and ducks and other waterfowl round things out
in November or so.

I guess birders get to enjoy a much longer fall than the rest of the
population!

Best,
Steve Shultz
Cary, NC






Paula Jeannet Mangiafico <paula.mangiafico@duke.edu>@acpub.duke.edu on
07/23/2001 04:22:45 PM

Sent by:  carolinabirds-owner@acpub.duke.edu






To:   carolinabirds <carolinabirds@duke.edu>
cc:
Subject:  Re: Fall migration?


I was struck by all the references to migration.  Amateur that I am, I
always assumed migrations started when the weather got just a little
cooler.
But July???  What factors drive the timing or the actual start date of
migrations?

Paula Mangiafico
Southern Durham Co.


----- Original Message -----
From: "L & J LENTZ" <LJL@ETINTERNET.NET>
To: <carolinabirds@duke.edu>
Sent: Monday, July 23, 2001 3:09 PM
Subject: Fall migration?


>
> Sunday and today I've had an invasion of black and white warblers.  Don't
> know the size of the flock, but it seems they were everywhere. I really
> enjoyed seeing so many in the big trees in my back yard. Has the fall
> migration begun already?
>
> Has anyone else noted the decline of black-and-yellow Argiope, sometimes
> called "writing spider".  I have not located a single one in my yard this
> year.
>
> Lucille Lentz
> Richmond County, NC
> ljl@etinternet
>
>
>


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