Date: 4/24/24 9:16 pm From: Mark Holmgren via groups.io <maholmgren33...> Subject: Re: [sbcobirding] New Calliope UCSB + Hummingbird Musings
Good question, Alex,
What happens in SB County is just as likely to be a function of events
elsewhere as anything that facilitates or constrains birds locally.
We have seen isolated events along the South Coast that look like prolonged
staging of, especially, migrants headed for montaine breeding habitats.
But this appearance of 'staging' is not a regular thing. The prolonged
abundance of Calliope and Rufous Hummingbirds at low elevations may be
driven by the unavailability of habitats at higher elevations. There is
extensive snow this year in the Sierras, I believe.
Tests of this hypothesis might be
a) look to see if this staging is occurring also in lowland Ventura and LA
counties,
b) ask if this is occurring in other migrant species headed for high or
higher elevations (Robins, Hammond's Flycatchers, Olive-sided Flycatchers,
for example)
Mark Holmgren
San Marcos Pass
On Wed, Apr 24, 2024 at 2:08 PM Alex Castelein via groups.io
<alex.castelein...> wrote:
> Hi all,
>
> I just had a new male Calliope on campus, this time in the bottlebrush row
> by Student Health.
>
> Obviously this is a pretty good year for them, but there’s 2 things that
> confuse about it, if anyone has any insights:
>
> 1- I was under the impression that wet years like this one were worse for
> Calliopes by the coast, because they have plenty of blooming flowers along
> their usual migration routes. I’ve heard it suggested that the prolonged
> cool weather is causing some effect (keeping blooms minimal and/or just
> keeping the hummingbirds lower elevation where it’s warmer), which could
> explain the good numbers of Rufous and Black-chinneds so far as well.
>
> 2- All reports I’ve seen that have a description or photos are of males.
> Where are the females? Is it typical for us to get a very skewed ratio?
> I’ve noticed a similar situation with Black-chinneds, with far fewer
> reports of females. I’ve personally seen 5 males and only 1 female.
>
> I’d love to hear any thoughts/hypotheses people have, especially from the
> more experienced birders who’ve seen hummer migration play out many years
> here.
>
> The bottlebrushes/eucs also had several western tanagers and a nashville
> warbler.
>
> Cheers,
> Alex Castelein
> UCSB/Isla Vista
>
>
>
>
