Regarding "concern" about HOSP decline in North America, I have one
word: good. WHENEVER an "alien" species [be it plant, snake,
mongoose, or bird] that is hearty/hardy invades (or is intentionally
introduced into) an otherwise previously unused ecosystem, it is
"usually" more successful than closely related or other natives,
probably because natives lost the necessity to compete, having
already "won" their place locally/regionally. House finches "seem" to
be supplanting Purple finches in Eastern North America as well, since
that fateful and unfortunate release of illegally "for sale" birds in
New York (in early 20th century?)... They then "exploited" (oooo how
terrible) a niche that "local" birds (evolved over millenia if not
millions of years) either did not or could not use.... In addition,
inter-specific food and nest site competition may be involved (life
style / reproductive strategies, etc) -- more likely something else,
since PUFI may concentrate feeding on different items and seem to
nest on branches, while HOFI nest in/on whatever they can find,
including our homes, barns, cars and trucks. I've observed MORE PUFI
in CA feeding on berries than HOFI, and their respective PLACES of
feeding (interior, edge for PUFI, ground and anywhere for HOFI) may
play big part in success. Similarly, HOSP seem to LOVE cattle,
ranches, office buildings, garages, McDonald's (no endorsement OR
denigration), etc.... - Jim Greaves

At 01:01 PM 3/25/2010, tweeters-request at mailman2.u.washington.edu wrote:
>It is interesting to hear Dennis's concern re: a potential decline
>in HOSP and if true,a consideration of the variable explanations. In
>the U.K. and certainly in some major European cities, the species
>has been in a sharp decline for some decades, by over 50% in the
>last 40-50 years in the UK, and by 65% between 1997-2000. A recent
>study confirms this but cannot pin down the variable solutions -
>decline in invertebrate prey is in association with the decline, and
>loss of deciduous trees, shrubs and grassland in suburban areas is
>another factor. HOSP chicks showed starvation during the first 6
>days in the nest. Whether competetition with other species that use
>invertebrates to feed the young within urban areas is a factor is
>not clear, but there are strong declines in rural areas too. In
>Greater Seattle we have seen Rufous Hummingbird and Purple Finch
>replaced by Anna's Hummingbird and House Finch without quite
>understanding why. But first whether there is a real decline in !
> the House Sparrow must be established.
>
>--
>David Hutchinson, Owner
>Flora & Fauna: Nature Books
>Discovery Gardens: Native Plants
>3212 W.Government Way
>Seattle,WA.98199
>http://www.ffbooks.net/
>206-623-4727