Subject: MIDWINTER BARN SWALLOWS IN THE NORTHWEST
Date: Jan 19 22:02:24 2002
From: Tangren family - tangren.family at verizon.net


I believe like Wayne Weber that it's hard to equate "early" swallow migration
with warbler finds. Perhaps elaborating, but not totally agreeing with his
insight, migration to a swallow may not be the same thing as migration
to a warbler, and the difference fits well with the "Pineapple express"
theory.

Warblers and other birds we might regard as Neotropical migrants are
actually more members of the Neotopical avifauna than they are of
the Nearctic. They move north in spring to take advantage of better
breeding habitat. When breeding is accomplished they return home (south).
Northbound migration may be triggered by daylength as hormone levels
change.

Swallows, along possibly with other birds such as robins and bluebirds,
might better be regarded as members of the Nearctic avifauna. Their
migration is a withdrawal from the north as food becomes scarce. As
warm weather, and more importantly food abundance, returns north
they follow it back home (north).

Barn Swallows could easily be caught up in the "Pineapple express" as they
follow the best source of food. Tree swallows would be less likely to
be affected because they typically winter farther north and thus may be
dependent on a different food source.

I know this is a gross simplification, but it says that migration is
a catch-all term for the seasonal movement of birds to areas that
promote survival and reproduction. The factors behind migration
are not the same from species to species.

--Jerry <tangren.family at verizon.net>
E. Wenatchee WA

>Birders,
>
>Wayne Hoffmann, in the attached note posted to OBOL on Jan. 14,
>wondered about the origin of the swallows, mainly BARN SWALLOWS,
>reported from numerous localities in late December and January from
>southwestern BC and western WA and OR.
>
>In a nutshell, I'll offer my opinion. This is NOT "early migration",
>and the birds were NOT "here all along and not noticed" (2 of the 3
>possibilities suggested by Wayne). My hypothesis is that these were
>birds caught up in the "Pineapple Express" (persistent warm,
>southwesterly winds) which dominated the weather of the Pacific
>Northwest for the first 2 weeks of January, and carried up here from a
>point of origin many hundreds of miles to the south.
>
>This is not "unprecedented", at least not if BC and WA records are
>taken into account. Similar incursions of Barn Swallows in January and
>February have been observed previously, at least once involving a much
>larger number of birds. However, I have not seen any sign of this
>phenomenon until about the last 5 years or so.
>
>A partial list of winter reports of BARN SWALLOWS on the Northwest
>Coast this winter is as follows:
>

....

>
>The only records of TREE SWALLOWS I could find were the following:

....

>
>Clearly, most of the invading swallows were BARN SWALLOWS.
>At Vancouver, B.C., this species does not normally arrive until the
>first week of April, and the earliest "spring arrival" date I have is
>March 24. So I feel confident in saying that these birds were not
>"early spring arrivals".
>
>At the same time, at one location-- the Reifel Bird Sanctuary near
>Vancouver, BC-- a few BARN SWALLOWS remain until late November or
>early December every year, and in at least two winters, were seen
>daily into early January (until the first hard freeze). At this
>location, a few midges can be seen flying about most days in November
>and December when temperatures are above freezing. However, this
>pattern of tardy departure (which has persisted since the late 1960s)
>does not explain the sudden appearance of Barn Swallows in mid-January
>or February in places where they had not been seen for months
>previously.
>
>The situation with TREE SWALLOWS is different. This is an early spring
>migrant, which normally arrives in Vancouver by late February, and has
>arrived as early as February 10. Nevertheless, January or early
>February sightings of this species, in my opinion, are probably due to
>long-distance movement of birds associated with a flow of warm air
>from the southwest.
>


....

>In short, my conclusion is, "blame it on the Pineapple Express"! The
>phenomenon of winter swallow records would certainly be worth a more
>detailed and comprehensive analysis.
>
>Comments, anyone?
>
>Wayne C. Weber
>Kamloops and Delta, BC
>contopus at shaw.ca
>
>
>
>----- Original Message -----
>From: <whoffman at pioneer.net>
>To: Obol <obol at lists.orst.edu>
>Cc: Obol <obol at lists.orst.edu>
>Sent: Monday, January 14, 2002 8:49 PM
>Subject: Re: Steigerwald Lk NWR Swallows
>
>
>The swallow sightings this winter are unprecedented in my
>experience -- odder than the warbler finds. Does anybody know what is
>going on with swallows in other western states? My recollection is
>that there was a gap in late fall without swallow sightings, so I am
>wondering whether a) they were here all along and not noticed? b)
>moved in from somewhere else in North America? or c) are VERY early
>northbound migrants?
>>
>>
>Wayne Hoffmann