Subject: Louisiana Hummingbird Banding - Winter 2003-2004|
From: Nancy L Newfield colibri@WEBDSI.COM
Date: Mon, 19 Apr 2004
Louisiana Hummingbird Banding - Winter 2003-2004The following is a summary of the hummingbird banding activities of Dave Patton, Linda Beall, Mark Myers, James Bell, Paul Dickson, Steve Locke, and Nancy Newfield over the course of the 2003-2004 winter season in Louisiana. Patton, Beall, and Newfield are self-employed, permitting some flexibility in scheduling. Myers is the curator of birds at the Audubon Zoo. Bell works for an international petroleum company. Dickson manages a large business. Locke is a University of New Orleans graduate student who worked in tandem with Newfield much of the time.
Most hummingbirds were banded in the southern third of the state, roughly the area south of the Interstate 10/12 line. Patton covered the area from Baton Rouge westward, while Newfield and Locke banded from Baton Rouge eastward, excepting St. Tammany Parish, which was primarily handled by Beall. Beall and Newfield both banded in Baton Rouge and probably caught only a fraction of the hummers around. Myers and Bell covered scattered areas around New Orleans and Slidell. Dickson examined a small pocket of wintering hummers in the Shreveport area, far removed from the hotbed of other wintering hummers.
The Louisiana Winter Hummingbird Project differs substantially from passerine migration banding studies. Most sites host only a few hummers, so efforts must be made to catch individuals rather than mist-netting whichever birds might pass through during a specific time period. Most captures are made using cage wire traps placed around feeders. Electronic remote-control releasers permit the operation of several traps at one time. Mist nets and other types of traps are occasionally employed. Because of the dispersed distribution of the birds, operations must be completely portable.
Almost all birds were color-marked, using non-toxic acrylic paint or specially-colored, water-soluble Liquid Paper on their crowns. Color-marking allowed us to avoid repeatedly capturing the same birds and it permitted hummerhosts to specifically identify each individual. Color-marking enabled the hosts to distinguish look-alikes and to notice unbanded birds as they arrived. Color-marked birds are more noticeable as they moved from one site to another as well. In several locations, we found more individuals present than had been originally tallied by the hosts. In most locations, the roster of individual hummers did not remain constant. Instead, while many individuals defend territories throughout the winter, others seem to be trap-lining over a fairly large area. This required the banders to make two or more visits to a number of sites as unbanded birds replaced individuals that had already been banded.
The project was initiated in 1979 as a means of documenting the numbers and species assortment of hummingbirds that spend the winter months in Louisiana. Traditional wisdom of the 1970s was that any hummers occurring in Louisiana during the winter months were vagrants or they were Ruby-throated Hummingbirds that forgot to migrate after the nesting season. The Louisiana list of hummingbirds was 5 species in 1974. There are now 11 species on the Louisiana list!
In the 1970s, most guides to hummingbird feeding dictated that feeders be removed by early September so that the ready availability of nectar would not cause hummingbirds to linger too long into the fall. At that time, it was thought that nearly all hummers that attempted to spend the winter in the area perished in cold weather and therefore spending the winter months in Louisiana was not a good strategy for survival. However, we have not found any Ruby-throateds banded during the usual period of breeding or of southward migration to remain for the winter. Therefore, members of Louisiana’s only nesting species that arrive in late autumn belong to other, as yet unknown populations.
The season, as we define it, begins with the arrival of the first non-Ruby-throated Hummingbird in mid summer. Typically, the first arrivals are adult Rufous Hummingbirds in August and most of those are returnees from previous seasons. During the early part of the season, we primarily attempt to verify returning hummers. Later, as several birds stake out territories at a site, we try to capture and band as many as possible. We also attempt to capture marked birds that have moved in from other sites.
Because the last stage of Ruby-throated southward migration may extend well into December, it is very difficult to categorize individuals of that species as winterers or migrants early in the season. Therefore, we arbitrarily define wintering for Ruby-throateds as those we encounter on or after 15 November, though some of those birds may actually be tardy migrants and some that occur earlier may well be winterers.
The winter banding season peaks in January and February, when maximum numbers are present at the various sites. The season usually ends in late February or early March as wintering birds begin leaving and summer resident Ruby-throateds begin arriving. At that time, wintering birds become more difficult to catch and banding trips become less productive. However some wintering birds stay well into April or even early May. This season many individuals remained by late March and banding continued until the month was nearly over. .
Totals for the 2003-2004 season are:
Explanation of terminology: Bird banders often use specialized terminology when discussing their favorite subject. Returnee a bird that has returned to the specific wintering site where it was banded after having been away for its putative breeding season. Foreign Re-encounter any subsequent capturing of a banded bird after it leaves the 10-minute block in which it was banded. A foreign re-encounter can be the capturing of one of our own birds at a distant site within Louisiana. The total of foreign re-encounters does not include several birds banded during the season that were re-encountered elsewhere as the season progressed.
This number of wintering hummingbirds banded exceeds the previous high count of new individuals by 28. The previous high count, documented in 2001-2002, was 482 individuals of 8 species [+ 55 returnees + 2 foreign re-encounters]. The total of returnees and foreign re-encounters raises the total of birds handled to 602, a very high mark. Several banded hummers thought to be long-term returnees declined offers for a “free inspection” and their band numbers could not be confirmed. [To read previous Louisiana Hummingbird Banding Winter Reports, log on to http://losbird.org/ and scroll down to “Hummingbirds”.] The diversity of species banded was one more than in the previous winter season.
It is not clear whether the number of hummers spending the winter months in Louisiana is increasing or not. Certainly methods for finding them have improved markedly. And, the increase in banders permits better coverage. The concepts of "better networking" versus "actual increase" can be debated endlessly without resolution. Both factors are probably at work. The network of hummingbird hosts has expanded greatly and the practice of creating habitat for wintering hummers has become very popular in southern Louisiana. Few Louisiana hummerhosts rely on feeders alone. Better communications, particularly through the listserv Humnet, has given us the means to reach more people interested in hosting hummingbirds during the winter months.
As usual, Rufous accounted for the largest number of individuals both new bands and returnees. Although Rufous has always been the most numerous species, the percentage of Rufous among the total population has risen in the past few years. This season that percentage was just shy of 65%, slightly lower than last season.
The number of wintering Ruby-throateds was not especially impressive. However, the number of documented returnees was very good compared to previous years. None of the returnees was known to be present during the summer months though 1 male that had been banded the previous November appeared as a southbound migrant in September at the site where he had originally been caught.
Black-chinned numbers edged close to the record total of 80 in 2001-2002 and the total of returnees was better than usual. Buff-bellied totals reached the highest ever since winter banding began and the number of returnees was excellent. Calliope numbers dropped a bit from the previous season as did those of Allen’s. However, an immature male Allen’s banded in Shreveport was the first of its species documented anywhere in northern Louisiana. Broad-taileds continued to be quite rare, but for the second consecutive season, a young male remained the entire winter in Shreveport, where he was banded. Broad-billeds are genuine rarities and have never been a major component of the winter population. No Anna’s Hummingbirds were reported anywhere in Louisiana.
Banders elsewhere in the southeast captured 4 Louisiana-banded Rufous. Mississippi, Alabama, and North Carolina each hosted an individual that had been banded in the state the previous season. The fourth bird was banded in the fall of 2003 and it continued on to Alabama.
Louisiana banders caught hummers banded in other states as well. A Raisin, Texas-banded Buff-bellied was caught in Lafayette for the second consecutive year. During the intervening summer months, this bird was captured several times at its original banding site, providing documentation of its whereabouts in winter and summer as well a first in hummer banding history! This bird was recaptured again at the original banding site just 12 days after departing Lafayette in March 2004! The distance between the two sites is 316 miles. A male Rufous caught in Houma proved to be one banded in Alabama the previous season.
A few individuals banded in previous seasons returned to Louisiana, but chose different sites. We can only speculate on the cause of the site infidelity.
Same-season re-encounters support a theory that not all hummers establish territories on their wintering grounds but rather drift about filching nectar from the territories of other hummers. This behavior is probably also practiced on their tropical wintering grounds where they must compete with native species, some of which are much larger than they are. Ruby-throateds, Black-chinneds, and Calliopes seem especially prone to wander. This season, individuals of several species were found to be wandering, including Broad-billed, Rufous, and Broad-tailed!
Returnees are the heart and soul of the project. These resourceful birds prove winter survival, indicate wintering site fidelity, and provide data concerning longevity. The number of proven returnees, representing 6 of the 8 species, attests to the value of the enhanced or created habitats.
The oldest returnee this season was a female Rufous dubbed “Old Mama”. She was an adult when banded in January 1997. Thus, she would have hatched in the 1995 or earlier breeding season. She has returned to the same beautifully landscaped yard in Abita Springs every year since. Using the standard Bird Banding Laboratory method for calculating age, she is now at least 8 years 9 months old. This age surpasses the longevity record for Rufous posted on the BBL web site and probably establishes a new record for the species.
Another female Rufous returned to her winter home in Gramercy for a fifth winter. She was a youngster when banded in February 1999. Several individuals returned from the winter of 1999-2000.
Another old-timer was a female Calliope that was already an adult when banded in December 2000 and returned to the same garden in Folsom the next year. She was absent in the 2002-2003 season, but returned again this season.
Weather can play a significant role in this project. We do not band during subfreezing temperatures or during heavy rain, but neither was a major factor this winter. Dense fog can impede travel, though at no time did it become dense enough to cause us to abandon a planned trip. Part of the region experienced a brief period of frost during January. This episode reduced flowering of many tropical and subtropical plants, making hummers somewhat more dependent on feeders and thus more readily caught, but in the more southern portion of the region, flowering continued unabated all winter. Natural nectar and insects seemed to be available at all times.
The Louisiana Winter Hummingbird Project has benefited from the enthusiastic assistance and generous financial support of numerous people. Many hummerhosts opened their doors at ungodly hours and sustained us with strong coffee, juice, breakfast and lunch. Several maintained a running tally of birds in their cities or towns and set up banding schedules for us. Others wrangled equipment, trapped birds, and recorded data. We thank Frank Arthur, Mahlon Ayme, Lynn Becnel, Laurie Binford, Franny Borello, Jane Carlson, Olga Clifton, Paul Conover, Miriam Davey, Dennis Demcheck, Kay Drouant, Bill Fontenot [Lafayette Nature Station], Bob Jumonville, Beth and Sammy Maniscalco, Rose and Jack Must [Wild Birds Unlimited, Lafayette], John and Margaret Owens, Ron Stein, Melanie and Pat Stephens, Gene and Edna Street, Tom Sylvest, Mike Taylor, Pam Toschik, and Chris and Satya Witt for the many hours they have invested in this project. We appreciate their special help - and we are already looking forward to next season just 3 1/2 months away!
Nancy L Newfield
Metairie, LA USA