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Checklist S48966991

 
Location
Tilden Nature Area, Contra Costa County, California, US ( Map ) ( Hotspot )
Date and Effort
Fri Oct 05, 2018 8:30 AM
Protocol:
Traveling
Party Size:
40
Duration:
3 hour(s)
Distance:
1.12 mile(s)
Observers:
Alan Kaplan List , Erica Kawata List , Johan Langewis List , Krehe Ritter List , Lee Friedman , Pam McKown List , Rebecca Robinson List , naregr roubinian List
Comments:
Golden Gate Audubon Society First Friday Birdwalk, October 5, 2018. Tilden Nature Area, parking lot to Jewel Lake and back by way of the boardwalk. Topic today was again feathers: Ptilochronology (the study of feathers through time), growth bars (the growth cycle of a feather is marked off each 24 hours by a dark [daylight-deposited] and light [night-time deposited] pair of bands), and is evidence of the nutritional status of the bird during the feather's development. The field is only 30 years old (Thomas Grubb's first paper using ptilochronology was published in 1989) but there is enough research that Grubb published Ptilochronology: Feather Time and the Biology of Birds (Oxford University Press), in 2006.
Species
35 species total
2
3
2
1

Great Egret Catches Fish

ML117593371

© Lee Friedman

Average Quality
ML130705751

© Lee Friedman

1

makes it official!

2
1
1
1
ML117593831

© Lee Friedman

Average Quality
2
ML117592931

© Lee Friedman

Average Quality
3
4
ML117593241

© Lee Friedman

Average Quality
1
1
2
2
2
3
4

Bird O'the Day: lots of singing!

ML117592811

© Lee Friedman

Average Quality
1
1
1
1
3
1
ML117592601

© Lee Friedman

Average Quality

Juvenile Cedar Waxwing below Pacific-Slope Flycatcher

Age:
Juvenile
5

feeding on thistles on the Jewel Lake sandbar

ML117593421

© Lee Friedman

Average Quality
1
5
2
3
1
3
1
ML117593551

© Lee Friedman

Average Quality

Black throat is seen clearly

ML117593711

© Lee Friedman

Average Quality

Small yellow spot by eye is just visible

ML130705781

© Lee Friedman

1
ML117593071

© Lee Friedman

Average Quality
1
 

Are you submitting a complete checklist of the birds you were able to identify?

Yes