Date: 12/31/25 9:25 pm From: Conor McMahon via groups.io <conormcmahon22...> Subject: Re: [sbcobirding] Santa Barbara CBC date
Hi all,
I was curious about this so I checked the rainfall records maintained by
County of SB. These are really very detailed and spatially explicit, so
they're worth digging through if you're interested in this kind of thing:
Since 1951, 26.1% of days in the Dec. 29 - Jan 5 time block have been rainy
in Goleta, vs. 20.2% of days from Dec. 14 - Dec. 21 window. So the later
period is a little bit rainier, but really not by enough to make much of a
difference for planning reasons. There's a similar (smaller) difference in
total rainfall amount between the two, as well. My impression is that in
the next century the region is forecast to get relatively little change in
total rainfall amount, but increasing intensity towards the middle of the
season (Jan/Feb) and less rain towards the shoulders of the rainy season,
which would likely reduce the overall problem more by moving more rain
outside the CBC period (although obviously also having a lot of other
potentially interesting/negative effects).
As a compiler for the last couple years, I think a more important factor
for the schedule is avoiding holidays and associated travel/obligations.
It's not clear to me whether the current or earlier time would be better
for that aspect. I do think during basically any time in the allowed CBC
window (12/14 - 1/05) it's guaranteed that most UCSB students are
unavailable to participate, which has often felt like a loss given that so
many of our high quality habitats are close to campus. The later dates are
probably a little more likely to be good for students because most students
leave after classes end (before the start of CBC season) and come back
after New Year's or thereabouts.
Personally though I think consistency with the existing record is much more
important than any benefit we'd get from moving back and forth in terms of
either weather or participation. The count has had its current time since
1976, which is most of its history.
Worth keeping in mind too that although we like to run up the species total
count as much as we can for sporting reasons, rare species documentation is
really not the purpose of the is CBC and those data are intrinsically less
valuable than monitoring long-term population shifts in "normal," expected
birds. I'd rather focus on getting a relatively more consistent estimate of
White-crowned Sparrows than how many orioles or unusual warblers we have in
a given winter.
Best,
Conor
On Wed, Dec 31, 2025, 4:09 PM Nick Lethaby via groups.io <nlethaby=
<proton.me...> wrote:
> All,
>
> Since we are potentially facing another rainy count day, I am wondering if
> any thought has been given to changing the date of the CBC in future years.
> The current date puts us much more in the main rain period than
> mid-December. There is also a fair amount of evidence that some of the
> scarce wintering birds often move on in mid-late December, possibly due to
> colder wetter weather.
>
> Nick Lethaby
> Goleta, CA
> <nlethaby...>
> +1 805 284 6200
>
> Sent with Proton Mail <https://proton.me/mail/home> secure email.
>
> --
>
> Nick Lethaby
> Goleta,CA
>
>
>
