Migrants, CSR El Paso Co, Friday

[Steven Brown]

Hey COBirders,

Not big numbers, but more migrants arrived early this morning. There were noticeable small birds moving around, unlike all other days so far.

Best:

5 Yellow Warblers, including 2 FOY females
Com Yellowthroat, plus FOY female
FOY Ad M Yellow-breasted Chat
FOY Ad M Bullock’s Oriole
very few sparrows seen today. Maybe the White-crowneds finally vacated.

25 birds banded Thursday, 15 Friday.

A Banding Story….Besides banding passerines to see migrant numbers and diversity, I also am interested in Site Fidelity. Several of the species I band at Clear Spring Ranch do nest here, and I can catch them both in spring when they arrive, and sometimes in August/September before they depart again. I have many individuals that have been seen spring and fall over several years!

One female Yellow Warbler today was banded 5/8/2019 as a second year bird (hatched in 2018). I recaptured her 5/20/20, and today, 5/7/21. I have not seen her in the fall yet, so I am not sure if she is nesting here, or further north somewhere, and just passes through CSR. More to be learned!

In his new book, Sibley suggests that about 1/2 of each age class will die each year. (so while species may “mate for life” there is a real good chance their mate will change several times.)
If she hatched in 2018, 1/2 of her age class was gone by spring 2019, 1/2 again by 2020 (1/4), and 1/2 again by 2021. So she may be part of 1/8 of the survivors in her age class, after just a few years. Nevertheless, assuming she hatched nearby, she has migrated successfully at least six trips so far, and that’s pretty cool.

Have a good weekend,
Steve Brown
Colo Spgs

[Ann Luckado]

Very cool!!!

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