Salmonberry and currant are important early forage crops for
hummingbirds, but hummingbirds along the Oregon Coast arrive
well in advance of blooming of either of these species and
they arrive because of day length not because the flowers
have bloomed.

The literature is rife with this statement about flowering
plants as if the birds can somehow sense when the flowers
are coming into bloom. Flower blooming and hummingbird
arrival are closely synchronized events, both controlled
by daylength and they have come to be so timed by natural
selection. But in the case of hummingbirds, the northward
movement, latitude by latitude is ahead of most bud burst.

Here's an experiment: Let's inventory flowering plants
when we hear about the arrival of hummingbirds in our
area. I predict that latitudinal arrival occurs before
significant blooming mostly along the coast and western
interior valleys (this is my hypothesis). Further (second
hypothesis requiring a different data analysis) longitudinal
dispersal will be more closely correlated to flower blooms.

And now all us citizen scientists have something to test
through observation and experiment.

My Theoretical Model: Hummingbirds arrive in our area
before the food source along routes where the weather
is, on average, mildest and disperse into less temperate
areas as the conditions change.

And the beauty is: I could be wrong and if I am we all still
learn something.


WAYNE WEBER wrote:

> The arrival of Rufous Hummers in southwest B.C. seems to be timed
> to the flowering of Salmonberry (Rubus spectabilis) and Red-flowering
> Currant (Ribes sanguineum), whose flowers are major food sources for
> hummers. Salmonberry is noted for its long flowering season, with some
> plants always in bloom by late March, but most not reaching full bloom
> till well into April. If most of the Rufous Hummers arrived here in
> late March, they'd probably starve.
>


--
Mike Patterson Alas, to wear the mantle of Galileo,
Astoria, OR it is not enough to be persecuted
celata at pacifier.com by an unkind establishment,
you must also be right.
---Robert Park
http://www.pacifier.com/~mpatters/bird/bird.html