Birders,
The two obvious adult Tundra Swans, one with extensive yellow on the bill and the other with a small yellow tear drop, are the likely parents of the immature. This family group acts as a unit and they are rarely separated by very much space. One adult has extensive yellow on the bill, the other more of a small tear drop. The immature is dusky and has a pale spot on the bill that hasn't yet turned yellow. It has V-shaped forehead feathering, demonstrating the weakness of this field mark on immature birds.
The fourth bird is another adult, and is the head-scratcher. It spends more time by itself, often traveling over to the Valmont lakes. It is the individual recently photographed by Kyle Medina over at Sawhill Ponds (refer to his COBirds post from this morning "Swan- Sawhill Pond 2/24/17"). It is maybe slightly larger than the other swans, and the neck looks a little more sinuous and the back maybe more rounded. These features give it a resemblance to a Trumpeter. It currently has some heavy staining on the head and neck, which helps pick it out from a crowd, but is not something that's useful for ID. The thing is that it does have a pale spot on the bill in front of the eye- not bright yellow like the other Tundras, but more of an off white. The forehead feathering is also U-shaped, as in an adult Tundra. The legs are dark black, which might help rule out a "white morph" Trumpeter as described in David Sibley's blog post linked below. There's a good chance it's a Trumpeter x Tundra. Steve Mlodinow has extensive experience with both species and their crosses, so he might have more to chime in on that hypothesis.
A handy link to Kyle's photo: http://tinyurl.com/hpe7det
Some good reading: http://www.sibleyguides.com/2011/07/trumpeter-swans-with-yellow-loral-spots/
 | www.sibleyguides.com Related posts and pages: Trumpeter Swans, yellow bill spots, and leucism In a previous post I've talked about Trumpeter Swans with yellow bill spots as a... | |
Thanks,
Christian Nunes
Longmont, CO
Sent: Sunday, February 26, 2017 4:28 PM
To: snowy.owlets@gmail.com; Cobirds
Subject: Re: [cobirds] Swan #4 at Cottonwood Marsh
--Hi Everyone,
A fourth swan has just come in. It looks and sounds like a Trumpeter.
Mark MillerLongmont, CO
Sent via the Samsung Galaxy S® 5 ACTIVE™, an AT&T 4G LTE smartphone
You received this message because you are subscribed to the Google Groups "Colorado Birds" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscribe@googlegroups.com .
To post to this group, send email to cobirds@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/ .64a0rvwa9idkmybacp3h4hy0. 1488122931978%40email.android. com
For more options, visit https://groups.google.com/d/optout .
You received this message because you are subscribed to the Google Groups "Colorado Birds" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscribe@googlegroups.com.
To post to this group, send email to cobirds@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/CAAPQkTv1grVKc78fA6Ssxz7Ms_SUW%3D530U5D6q_iFKSDYqdsDQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
No comments:
Post a Comment