Monday, December 5, 2011

Attempting to sight some color-banded birds at PRBO's Palomarin Field Station

The PRBO banding operation started in 1967 with the Palomarin Field Station located in Point Reyes near Bolinas, CA.  Since then they have banded tens of thousands of birds, as part of a long-term, constant effort study on populations, demography, and breeding success among other topics.  One of the methods that PRBO uses is color-banding.  For Western Scrub-Jays, Wrentits, Song Sparrows, White-crowned Sparrows, Spotted Towhees and previously California Towhees banders apply unique combinations of four color bands.  These bands allow you to identify birds at the level of the individual when seen in the field, since the unique numbers on metal bands are far too small to read when not in the hand.  This morning I set out to sight some of the birds around the field station, but with so many uncooperative birds, I only found two that I could get the full combination from, but I found other birds as well, many of which had metal bands but no color bands.
One of the many disobliging Song Sparrows that wouldn't allow a view of the full combination.  Although this bird at least posed for a second for a photo.  In this photo we can see half the combination, left leg = black over silver, but the right leg remains hidden. [Photo by Lukas Musher]
Although not incredibly obvious in the picture, this Song Sparrow has a combination of Left Leg = Green over Silver, Right Leg = Yellow over Mauve, or GS/YM in shorthand.  Once the combination is found we can plug it into PRBO's database to find out when the bird was first banded, it's age (if hatching year is known), its movement tendencies around the area (i.e. where it has been previously sighted and captured) and perhaps sex (if noted from the presence of a brood patch or cloacal protrusion in past captures).  This particular bird was first captured as a juvenal bird and banded on 7/18/2011, and has since been captured six times at several locations around the field station.  We know that this bird was must have been born earlier this year.  The bird has been seen recently multiple times around the parking lot for the banding lab. [Photo by Lukas Musher]
This Western Scrub-Jay was too far to accurately get the colors by binoculars, but thanks to 18 megapixels and a 400mm lens I can (see below). [Photo by Lukas Musher]
The combination here is Left leg = orange over blue over yellow, Right leg = silver. This bird has only been captured once in 2010.  [Photo by Lukas Musher]

This individual would not show it's left leg(!), but the metal band can be clearly seen on the right leg. [Photo by Lukas Musher]
If you look closely you can see the lone red color band on the left leg, but no others.  Western Scrub-Jays have powerful bills capable of destroying and ripping off poorly fastened color bands.  This individual is carrying acorns (note the one protruding from the throat, and slightly bulging crop).  [Photo by Lukas Musher]
Other birds were around too, and a little pishing turned up Red-breasted Nuthatch, Hutton's Vireo, Dark-eyed Juncos, Fox Sparrows, Golden-crowned Sparrows, and dozens of Ruby-crowned Kinglets and Chestnut-backed Chickadees.
This Red-breasted Nuthatch came in to see what all the pishing ruckus was about. [Photo by Lukas Musher]
One of the many banded Golden-crowned Sparrows at Palomarin. [Photo by Lukas Musher]
By Luke Musher

No comments:

Post a Comment