December Banding ActivitiesDuring the month of December, the permanent resident birds of the Concho Valley are usually joined by a number of winter residents that make banding slow but interesting. We started the month attending the Inland Bird Banders Association meeting in Weslaco, Texas. We certainly enjoyed meeting banders from all across the central United States and Mexico. We enjoyed the presentation of recent research projects and taking part in the banding demonstrations conducted by local banders in the Rio Grande Valley. Congratulations to Mary Gustafson and Mark Conway and others that hosted an outstanding conference.
We returned from that conference to find the weather in West Texas had taken a wintery turn. The remainder of the month was a mix of cool weather, wind and light precipitation with an occasional nice day mixed in the mix. We made two efforts during the month. The first effort was rained out but we made a good guess on the second effort and we had a good day of banding between the wet, windy days that dominated the month. On the second effort, we returned to the East Windmill Area where we set up our sparrow trap to band these winter visitors.
We banded White Crown Sparrows, Vesper Sparrows, Lark Buntings and Field Sparrows. along with Pyrrhuloxia, Western Meadowlarks, Red-winged Black Birds and a Red-shafted Flicker. It was a good day of banding to end an outstanding year at the Hummer House. We completed this year with 99 species of birds banded at the Hummer House this season. This replaces the old record of 84 species banded in a single season. We also added nine species of birds not previously banded there. A more extended discussion of this year's banding efforts is included below the photo slideshow.
Hummer House Banding 2011
IntroductionDuring the fall and winter of 2010-2011, the Hummer House along with most of the state of Texas was in the grasp of a historic drought and there was little hope that the drought would be over soon. With food and water in short supply across the area, many species of birds that are normally residents in the winter season were either present in very small numbers or totally absent from the ranch. So few winter birds were present that we concentrated our early season bird banding attempts on permanent resident birds and used the efforts as training opportunities for our banding team. Against this background, few knowledgeable birders could have predicted a long and successful banding season in 2011.
Along with these factors, our research goals for banding passerine birds at the Hummer House required that we shift most of the emphasis from banding at the headquarters to banding stations located at remote locations across the ranch. It was assumed that the total number of birds banded during the year would decrease dramatically since at least 80% of the passerine birds banded at the Hummer House in the previous fifteen plus years were banded at the feeding station near the headquarters and represented disproportionate numbers of seed-eating birds that gather at the feeding site. Although limited educational demonstrations during the current year involved banding at the headquarters, more than 95% of passerines banded this year were banded at our remote stations.These locations were the focus of three data gathering efforts. We began operation of a MAPS Station at the South Concho River Location (SCR-1) during the summer breeding season. We conducted migrant banding at the large spring (SPR) during spring and fall migration. The East Windmill area (EWA) was used as a banding site for late season migrants and winter residents. We collected data from all three locations for use in our Painted Bunting study. Although several years of data will be necessary for our research, we are confident that the number and species of birds banded during this year are more reflective of the populations residing in or migrating through this habitat. We also believe that we can begin to separate populations of target bird species residing near these stations.
The East Windmill Area will be further developed and become a primary banding site for our Painted Bunting Study during 2012. The SPR site has been expanded for the beginning of spring migration with the addition of a three level aerial net and three additional ground nets downstream from headwaters of the spring.Analysis
As expected, the total number of birds banded this year was well under the average for the past five years. This year's total of 2500 birds was approximately 1300 birds below the average. However this year's total consists almost entirely of birds banded randomly within the natural habitats of the ranch. The selection of our banding sites seems a larger factor than the effects of the drought on the total number of birds banded.
This deviation from the historical average was primarily caused by two separate factors. We were unable to band hummingbirds during the first two thirds of the banding season as we waited for approval of our Hummingbird Banding Permits. Although Kelly Bryan, Fred Bassett, and Bob Sargent banded hummingbirds during this time and helped us in our preparation, they were not present often enough to overcome the shortfall caused by our lack of a hummingbird banding permit. We banded 320 fewer hummingbirds this year than the five year average.Ninety-nine species of birds were banded at the Hummer House during this banding season. Fifty-four species were banded in numbers exceeding the previous records for these species on the ranch. Thirty-four species were banded in numbers equal to or above the historical average for the ranch. Eleven species were banded in numbers well below the historical average. Eight species were seed-eating birds that in the past have been banded almost exclusively at the headquarters feeding grounds. This year, they were banded in small numbers at the remote banding stations. We banded 1470 fewer of these eight seed-eating species as compared to the five year average. Two of these eleven species were hummingbirds whose numbers were impacted by the permit factor discussed above and one species was the Northern Mockingbird that does not commonly reside in two of three station areas.
The drought was probably a major factor in our banding this year but not in the manner anticipated. We started our year with the migrant banding study that is conducted at the large spring north of the headquarters (SPR). From the first, we had higher numbers of birds than we had previously experienced at that location. We also added new species of birds to the Hummer House banding list and encountered larger than expected numbers of previously rare species. In early May we opened the South Concho River MAPS Station (SCR). MAPS stations are designed to thoroughly sample the breeding birds in a confined area and typically produce limited records of banded birds. Less than one hundred birds per season is a typical number of records. We banded 53 birds in the first session and this trend continued throughout the summer. We finished the MAPS season with 320+ birds. The number of birds encountered during the fall migration season continued the trend. More often than not the nets at the SPR station had to be closed when our banding crew was unable to handle the volume of birds in a safe manner.Throughout migration and the summer breeding season, many more birds than normal relied on the riparian corridor near the SCR and SPR stations for food and water. With two out of three of our banding stations in the corridor, we banded more birds than could have been anticipated even in the best of years. Throughout both migrations seasons, we caught 89.7 birds per hundred net hours at the SPR station and 49.4 birds per hundred net hours at the SCR Maps Station. Both of these banding ratios are impressive by any standard. The number of birds per hundred net hours at SPR in 2010 was 52 and was 39 for 2009.
In addition to the numbers cited above, the variety of species was also well beyond what might have been expected. Ninety-nine total species were banded on the ranch during this banding season. This compares to a previous record of eighty-four species in 2009. That total included one cowbird species and three non-native invasive species that live on the ranch. No invasive species or cowbirds are included in this year's count. During this year, nine new species were added to the birds banded on the ranch and brings that total to one hundred and forty six. Twenty-eight species that were banded this year began the year with fewer than five specimens banded on the ranch during the past fifteen plus years. Eleven species had more specimens banded during this season than their grand total for the past fifteen plus years. Six more species missed this standard by a very small margin.Prior to this year, ninety-eight percent of all the birds ever banded at the Hummer House were members of the thirty-eight most common species banded there during the past fifteen plus years. In last year's terms, that left two percent of the birds banded to be spread over the remaining 98 species that had been banded there during this time. In plain words, a lot of birds have been banded there over time, but a large percentage of these were repeated bandings of the most common species. During this season we banded all of these most common species except the Inca Dove, Mourning Dove and the Mountain Bluebird. Due to the drought, there were very few Mountain Bluebirds present during winter and fall of this year. The Inca Doves and Mourning Doves have shown a decline in numbers over the past few seasons but we should have banded these species if we had spent significant effort at the feeding ground. The only White-winged Dove that we banded this season was banded at the feeding ground. Including the new species that we encountered this season, we banded 64 species of birds that until this current season were part of the two percent that were seldom banded. Sixteen of these 64 species breed on the ranch and several others are winter residents. Our systemic efforts within these natural habitats have given us an entirely new picture of the birds that reside within and migrate through these environments.
Given the chicken and egg nature of this season, one must ask the obvious question: were the numbers cited above caused entirely by the drought or did they result from the new emphasis on systematic banding efforts in remote areas of the ranch? It seems logical that the drought accounted for some of the shift in species populations and thus changed our results for this season. However, I believe that our systematic banding efforts throughout the season in three established station locations accounted for a significant percentage of our positive results.Although attempts were made to be consistent in all our efforts throughout the season, we did vary our schedule somewhat when we banded with Kelly Bryan in the Davis Mountains and when we were involved with hummingbird training at different times during the spring and summer. Line graphs involving catch rates for various species readily identify those times. Most unusual species were not netted in sufficient numbers to statistically analyze. However, it seems logical that if we fail to net expected numbers of more common species because of missed efforts, we also fail to establish records of unusual species during these times. Some species do not have an extended migration period. Failing to make efforts during a limited migration period could eliminate records of those species completely.
While the drought may not have been totally responsible for our banding records described above, it was the primary factor in the limited breeding taking place on the ranch during this season and will be a factor on the number of birds banded for years to come. The data gathered from our MAPS station is designed to measure the nesting success of our summer resident birds. Once nesting is completed, data is gathered to predict the survival rate of the offspring. The data from last summer indicates an extremely poor year for the reproduction of most birds. Based on our banding of hatching year birds, hummingbirds seem to have been the most successful of our breeding populations. Species such as Painted Buntings, Summer Tanagers, Lark Sparrows and some species of vireos were mostly unsuccessful. We have concern for the species within the next few years. The MAPS station is located on some of the most favorable habitat available for these birds. If they were unsuccessful there, the more arid habitats were also unsuccessful. Many breeding species stopped their breeding efforts and migrated out of the area well ahead of normal migration patterns. The seed-eating species that feed at the headquarters may have been more successful.There were two other notable records during the banding year. There are no previous breeding records of Black-and-white Warblers in the Concho Valley. During this breeding season, ten members of this species were banded at two of our stations. Adults and hatching year birds were banded throughout the summer giving a strong indication that these birds are making attempts at breeding in this area. The second event was the banding of five Baltimore Orioles during the fall migration season. Previously only one of this species had been banded within the previous twenty years. We banded five of these birds this year over an extended period in the fall migration. Reports from across the state indicate that many member of this species migrated in a more westward pattern than normal years. The drought was surely the primary cause of this shift. The trends that we established for Painted Buntings will be addressed in a separate report.
It is my sincere belief that the efforts undertaken this season at the Hummer House represent a true snapshot of the populations and movements of birds that are part of the ranch. We have attempted to make each effort a systematic effort that can be correlated mathematically and logically to the each of the other efforts made during the season. We anticipate continued successful efforts in the months and years to follow.