A Summary of Two Years' Trapping and Banding Hummingbirds on the lower San Pedro River
by SABO bander Bill Taylor.
Below: at left, Liz and Bill Liz Taylor working at the SABO banding table at Skeen's and Abbotts, May 22, 2005; at right, Bill holds an adult male Black-chinned Hummingbird.
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In April of 2005, with Liz, my wife and volunteer, we started trapping and banding hummingbirds on the lower San Pedro at the residence of Karole and Mack Skeen, 7 miles south of San Manuel. This was and is designed to be in conjunction with the Southeastern Arizona Bird Observatory (SABO) banding program at the San Pedro House at Sierra Vista. The San Pedro House program was started in the mid-1990s by Sheri Williamson, author of The Peterson Field Guide to the Hummingbirds of North America and her partner, husband and naturalist Tom Wood.
In May we were able to expand our project to Janet and Mike Abbott's place, some 36 miles south of Skeen's and 14 miles north of Benson on the same Cascabel Road. Both the Skeen and Abbott sites are heavily mesquite-bosque, compared to the savannah-like surroundings of the San Pedro House. We have been hoping to find some connection between what seems an obvious fly-way, albeit the two sites are some 75 miles and 39 miles north of the San Pedro House--as the hummingbird flies. Trap used was our Taylor bonnet trap, controlled manually and sometimes by radio.
Black-chins, Black-chins, Black-chins! Trapping for 3 hours in the early mornings, we banded 145 birds the first year--with just one Rufus hummingbird on Aug 8th at Skeen's. As anticipated, we had a wave of adult birds in the spring, either flying through or returning to settle into domesticity; and in the Fall we saw the adults headed south, to be followed later by the juveniles all on their own.
We carefully note species, sex and age; take measurements and weights and observe pregnancies and over-all condition before feeding and releasing them. However, an important additional benefit of a banding program is the opportunity to observe individual differences close up; to record unusual features and oddities, and more. We record these as well. Some excitement here--one adult female had in the recent past lost ALL her body and head feathers and was covered in little sheathed pin-feathers! Another bird had sores at the wrists of both wings. We could only assume she was nesting in some confined space--like the end of a two-inch pipe or gap in a roof eve--and was frequently striking the edges and keeping these little wounds open.
In 2006 we switched to banding the last 2 hours of daylight, up to 30 minutes before sunset, at the suggestion of Lorene Calder from her 30+ years of hummingbird experience and now volunteering with us. Either for this reason alone or it being a very different year on the San P., we banded 229 birds in 2006 (in 5 hours less total banding time). We saw an increase in Rufus hummingbirds (7) and added 3 more species--Broad-tailed hummingbirds (4), three Anna's hummingbirds; and one pert little Costa's female at Skeen's, face covered in yellow pollen, which had likely wandered in from the cactus-yucca covered desert hills just a hundred or so yards away.
Our average capture rate of 6.75 birds per hour in 2006 was virtually double that of the 3.7 birds per hour in 2005, albeit the shift from morning trapping to late afternoon trapping may have been a large factor, as well. *Note: of the 102 adult birds captured in the spring of 2006, 19 were returnees from 2005--a rate of almost 20% and above average for banding sites nationally. No hummers from San Pedro House, either year.
{We should note here we also banded one session at the mesquite-bosque ranch home of Charlie and Jeannine Thomas. Here we banded 12 birds and noted FOUR species!]
More oddities--a female Black-chin with the large head of a Camponotus sp. worker ant firmly attached just above the toes of her left leg yet under no apparent distress. The ant's head had evidently been there for some time: the flesh of her leg had grown over the pincers! Again, a male Black-chin had returned from the previous year with an ugly, suppurating sore mid-point on his bill. The previous year he had been noted with a smooth lump at the same site. The fun one, though, was the Black-chin male transporting 3 little yellow flower mites in his nostrils. (Of these we were successful in making a short movie clip through our field microscope.) Flower mites are harmless to hummers and may even signal to them the flower is drying out -- or dying -- as they leave the flower for a ride to fresher blossoms.
Environmental comparisons of the 2005 season and that of 2006 also give what we believe are important factors in the differences between the two. First, river drainage--much more water in the San Pedro in 2006, of course. USGS gauging stations at the Redington Bridge between the two sites registered zero cfs (cubic-feet-per-second) in June of '05 compared to 45cfs in '06, 676cfs in July of '05 to 6200cfs in '06, 9106cfs in August '05 to 19,490cfs in '06, and 2615cfs Sept '05 to 12,213 in '06. The Benson gauging station was down most of 2005 but 2006 data indicate July '06 at 2798cfs, August '06 at 7411cfs and September '06 at 5482cfs. Rainfall at an annual average of 10.49" was actually less for the year by some 3" in '06--but over-all below the 24-year annual average of 15.12".
Temperatures were higher in the spring of '06 than '05, higher in the late summer of '05 than '06 -- ranging from high 70s (F) to a blistering 107 degrees F. (This latter date was one of our highest numbers of birds, along with copious gnats and stinging insects.)
Volunteers have been many and especially appreciated. Lorene Calder, Joan Wike, Judy Showers, Trudy Duffy, Chuck and Susan Ostrander, Alona Banchi, Anna Young, Phillip Meredith, and Liz Taylor -- all traveled the distance, sat patiently for many hours and performed the functions of trapping, transporting, feeding and release, and, of course, the recording of data. Hosts Janet and Mike Abbott, Carol and Mack Skeen and Jeannine and Charlie Thomas at their Cascabel ranch site provided the essential sites--Janet and Jeannine were enthusiastic volunteers, as well. Thanks, thank you all for a swell two years. Thanks, too, to Susan and Phyllis and all the back-up volunteers at the Banning Creek Field Station for handling our often daunting record sheets. And the people of Saguaro-Juniper, Inc., who have been incredibly supportive throughout, providing environmental data and data sites through their web-site (www.saguaro-juniper.com).
Potential volunteers, possible hosts and interested observers are more than welcome to contact us coming into the 2007 season. E-mail address at btaylor@vhta.com, or simply call (520) 795 3832.
We're looking forward to it!
Bill & Liz Taylor