Date: 10/16/25 7:44 pm From: Alvaro Jaramillo via groups.io <chucao...> Subject: Re: [pen-bird] Red Crossbills at Skylawn Cemetery.
Joe and pen bird
When we found the Cassia Crossbills, there were other calls in there that
were likely the "Enigmatic" type 7 crossbill. Skylawn Cemetery may be the
most interesting Red Crossbill spot in all of North America!! The types of
calls that have gone through there are many, and it seems that oddities can
hang in there for some time. I am sure that it has to do with the makeup of
the conifers there, but most importantly the fact that it is right up on top
of a singular range that is isolated and essentially right along the coast.
Nothing like that is similar elsewhere in the West.
All crossbill calls are learned, ALL of them. But the learning and
copying of calls is something that they do for flock cohesion, and for type
matching (bill/ecological type matching). It is not random copying and
mimicry. Cassia Crossbills have been wandering widely away from Idaho since
the big fires there. Crossbills move massive distances when their core tree
or trees do not have food. All crossbills move. There is no such thing as a
resident crossbill, at least not long term. The Cassia situation is special,
but it was incorrect to think they were resident. It was better to have
thought of them as having a particularly stable food supply, such that for
long periods of time they did not move out of their spot. But large fires
did do this to them, with many records in Colorado, and later the ones in
California.
We need a really thorough genomic study of crossbills to sort out what
is going on, there are no birds like them. We can have sympatric breeding
without mixing (at least not commonly). Yet they can changeable home ranges
and next breeding season encounter an entirely different vocal type where
they breed. Nothing is quite like them. We need more data, and open minds to
sort out crossbills. I look forward to when more information is available.
-----Original Message-----
From: <peninsula-birding...> <peninsula-birding...> On Behalf Of
Joe Morlan via groups.io
Sent: Thursday, October 16, 2025 9:33 PM
To: <peninsula-birding...>
Subject: [pen-bird] Red Crossbills at Skylawn Cemetery.
This morning I visited Skylawn hoping to photograph the Red Crossbills which
have been reported there. My eBird list with photos, video and voice
recording is here..
I did not recognize the calls so I contacted some experts who said that the
call I recorded closely resembles type 12. However that type is centered in
the northeast and has only one previous California record. Another
possibility is the enigmatic type 7, the rarest call type with unknown call
variation and unknown range. For now it remains a mystery. I welcome other
opinions.
Some of you may recall when the Cassia Crossbills were at Skylawn October -
December 2023 with voice recordings by multiple observers confirmed by
experts. This would have been a first California record except that it was
not accepted by the CBRC. Perhaps for good reason. Cassia Crossbill was
described as a species with limited range confined to one county in Idaho.
Then records started in Colorado. But California was perhaps too far a
stretch for the committee when it became apparent that crossbills may
imitate other call types.
Regardless, it would be good to get better recordings of these birds. If it
can be confirmed they are type 7, I think that would be very interesting as
few such recordings exist.
--
Joseph Morlan, Pacifica, CA
