Date: Sun, 19 Mar 2000 14:48:24 +0000|
From: Nancy L. Newfield colibri@GS.VERIO.NET
Subject: Louisiana Hummingbird Banding - Winter 1999-2000
Louisiana Hummingbird Banding - Winter 1999-2000The following is a report of the hummingbird banding activities of Dave Patton and Nancy Newfield over the course of the 1999-2000 season. This 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 during the winter months were vagrants that perished due to cold temperatures or they were Ruby-throats that forgot to migrate after the nesting season.
The season, as we define it, begins with the arrival of the first non-Ruby-throated Hummingbird in late summer. A Green Violet-ear [documented photographically] that appeared in late June at a feeder in Lafayette clearly did not fit into the defined seasonal pattern and is regarded as a vagrant, but it was very welcome nonetheless. Typically, the first arrivals are in August and most 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.
The banding season 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.
Totals for the 1999-2000 season are:
All except one Rufous, which was banded in Bossier City, 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 covered Baton Rouge eastward. We both banded in Baton Rouge and probably caught only a fraction of the hummers around. The Lafayette area covered by Patton seemed to have fewer birds than usual, while Newfield's portion held enough to provide her a personal best.
The Louisiana Winter Hummingbird Project differs substantially from ordinary 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. Most captures were made using cage wire traps placed around a feeder. Mist nets and other types of traps were used occasionally. We are constantly seeking new and better capture methods. A remote electronic trap tripper, invented by John Owens, enabled Newfield to trap while doing other tasks and from the comfort of indoors and thereby increased her effectiveness. Thank you, John! All trapping took place in backyards typical of the area. Hummers were attracted to nectar-producing plants and feeders. At no time were feeders the only source of food.
Almost all birds were color-marked, using a non-toxic acrylic paint. Color-marking allowed us to avoid repeatedly capturing the same birds and it permitted hummerhosts to specifically identify each individual. It enabled the hosts to distinguish lookalikes and to notice new birds as they appeared. In several locations, we found more individuals present than had been tallied by the hosts. In most locations, the roster of individuals did not remain constant. Instead, while a few individuals defended territories throughout the winter, many seemed to be traplining over a fairly large area. This required us to make two or more visits to a number of sites as new birds replaced birds that had already been banded.
Weather can play a significant role in this project. We do not band during subfreezing temperatures or during heavy rain, but neither was a 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. However, the extremely mild temperatures that prevailed throughout the season created a superabundant natural food supply, which made the birds much less dependent on feeders and therefore much more difficult to catch. Several birds of rare species and several probable returnees could not be caught.
Returnees prove winter survival and give us data concerning longevity. The highlight of the season was the August appearance of a banded adult Buff-bellied Hummingbird at the Nowell home in LaPlace, a returnee, which had been an adult when banded in February 1993. Because this individual was an adult when it was banded, we can be sure it was hatched no later than the breeding season of 1991. This bird, nicknamed "Junkyard Dog" because of his irascible demeanor, set the longevity record for its species. This bird was not captured for verification until February at which time it was nearing 9 years of age.
A banded adult male Ruby-throated appeared in July at the Street home in LaPlace where one had wintered the previous three seasons, but it was not caught at that time, so we cannot be sure it is the same individual. That bird disappeared from the Street home in November and a few days later a banded adult male Ruby-throated was reported from the Nowell home .6 miles away. In January, it was captured and verified as the same individual that had been an adult when banded at the Street site in December 1997. An hour later, this bird was captured again at the Street home. At the same time, a Black-chinned, banded that day at the Nowell site, was also caught again. Then, the Ruby-throated returned to the Nowell home. A Calliope banded at the Street site that day later appeared at Nowell's.
An immature male Rufous, banded at the Beall home in Covington, turned up a few days later at the Owens' home about 4 miles away. It remained most of the winter. But, another Rufous, banded in February 1999 at the Hubbell home in Covington, was caught at Beall's in February 2000. The distance between these two sites is about .5 miles.
A female Calliope banded at Remsen's in St. Gabriel in February 1999 was seen at that site, but later appeared at the Cardiff-Dittmann home, where it was caught in February 2000. This is only the second Calliope return verified in Louisiana.
All other returnees were captured at the site where they were banded. After the aforementioned Buff-bellied, the oldest was a male Rufous banded as an immature in October 1996. 3 Rufous were returnees from the 1997-1998 season, while the remaining Rufous returnees, the remaining Buff-bellieds, and the Black-chinned were returnees from the 1998-1999 season.
A Buff-bellied banded at the Muth home in New Orleans in January 1999 was captured at the Weber home in Reserve in February 2000. It still bore traces of the original color-marking. The distance between the banding site and the recapture site is about 40 miles.
The data amassed this season provides valuable insight into the population of hummingbirds that regularly winter in Louisiana. Rufous Hummingbirds comprise a little over 50% of the hummers banded. In previous years, Black-chinned Hummingbirds ranked second in relative abundance, but this season, they were out-paced by Buff-bellied Hummingbirds. Ruby-throated Hummingbirds remain in fourth place. We find only very small numbers of the remaining species, but this season, their numbers were higher than ever before. Of course, most books will indicate that they are not here at all!
The movement of birds from one site to another within the season is excellent evidence that these birds know all the resources in the surrounding area and move about freely. Hummer feeding no doubt increases the rate of survivorship among wintering hummers, but the proliferation of exotic landscaping [not all by hummerhosts] is probably a greater factor. Questions regarding reasons for the phenomenon, routes used by individuals, and exact geographical origins remain unanswered, though there is no shortage of theories.
Although the number of individuals banded is an all-time high for the project, we still feel that many more hummingbirds are getting away unbanded. This project is very labor-intensive. Most of the banding actually takes place within the short January-February period and the limited number of days available is a limiting factor.
We are very grateful to the many hummerhosts for inviting us into their homes and permitting us to study their birds. Without their generosity and hospitality this project could not continue and grow. Numerous persons volunteered their time and skills to assist us in the field. We thank Laurie Binford, Carol Foil, Miriam Davey, Les Eastman, Cathie Hutcheson, John & Margaret Owens, Christie Riehl, Paul Conover, Bill Fontenot, Tom Sylvest, Lisa Robichaux, Dave Coignet, Lynn Becnel and Beth & Sammy Maniscalco for logistical support and help with capturing and recording data. Van Remsen, by creating Humnet, gave this project an enormous boost by facilitating communication and contact with new hummerhosts. Thank you, Van! Canines, Fritzel and Max, provided Newfield warm companionship on long drives. Perhaps, by next season, they'll have learned to operate the traps.
Nancy L. Newfield
Metairie, Louisiana USA
"Hummer Notes" - http://www.hummingbirds.net/