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Project FeederWatch
All quiet on the eastern front; a banner year Project FeederWatch is growing. This year 6,309 FeederWatchers contributed data, more than in any previous year. Welcome to all new participants! And welcome back to our steadfast, renewing participants. By the end of June, we had scanned 69,785 data forms—that's an average of nine data forms per participant. Some particularly motivated (and helpful) FeederWatchers sent 20 forms—10 on paper and 10 that they submitted electronically via the World Wide Web. These individuals were part of the group that we code-named "Penguins," our electronic data-entry testers. After connecting to the Lab's web site and entering their ID numbers and zip codes, Penguins gained access to screens that allowed them to submit their data from each count period. According to the feedback we've received so far, most Penguins felt that submitting data electronically was far preferable to filling out bubble forms. Alma Nygren of New Jersey spoke for many when she told us, "I couldn't wait to throw away my number 2 pencil." During the 1997-98 season, all FeederWatchers will be able to submit data electronically, but you don't have to get rid of your pencils yet. For the 1997-98 pilot year, you will also be able to send back data on the paper forms. What was the winter of 1996-97 like? According to many of the comments we received—mostly from FeederWatchers in the East—the 1996-97 season had few birds. From the eastern FeederWatcher's point of view, it was a "bad" year. But 10 years of FeederWatch data have shown us that this is inevitable—years of plenty are often followed by years with few birds. In 1995-96, eastern FeederWatchers reported seeing high numbers of birds at feeders, invasions of irruptive species, and increases in the numbers of non-irruptive resident birds. The picture was different this year. Irruptive species were practically absent from the East, and a mild winter resulted in fewer resident birds at feeders. For FeederWatchers in the West, however, this was an exciting year. Most of the irruptive species showed up in California and the Southwest, and many western montane species appeared at more feeders and in larger numbers than in the previous year. But when you're looking at a continentwide summary like this, it's important to consider how FeederWatchers are distributed across North America. Far more FeederWatchers live in the East than in the West, so these summaries are always biased toward what Easterners report. By focusing on regional results, we can obtain a clearer picture of how bird populations changed throughout the winter. Continentwide Most of the common resident birds visited approximately the same percentage of feeders as last year, but for 12 species the overall number of individuals decreased (Table 1). Hairy Woodpecker was the only species that increased by more than 10 percent continentwide, showing up at more northern feeders this year than last. The most abundant, widespread species may fluctuate slightly in numbers from year to year, but they have remained fairly stable over a 10-year period. The declines seen this year have two likely causes. First, nearly all irruptive species were absent from or were seen in reduced numbers in eastern regions. Second, many of the trends we observed in nonirruptive species in 1995-96 were reversed in 1996-97. In particular, increases in the numbers of several species of ground-feeding sparrows returned to their previous levels this year. Among the top 10 species at feeders, the House Finch declined most noticeably in numbers (Table 1). The percentage of participants who reported seeing House Finches in 1996-97 was identical to the percentage in 1995-96; however, a drop in the mean flock size caused an overall decrease of 22 percent in the mean number of birds reported. House Finches have been appearing at more feeders since Project FeederWatch began in 1987-88 (Figure 1a), but their numbers have been decreasing since the winter of 1992-93 (Figure 1b). Although House Finches are found at more feeders continentwide, their numbers are at or below 1987-88 levels. These declines have occurred only in the East; western House Finch populations are stable or increasing. We are currently investigating this decline in relation to the House Finch Disease Survey, and we will be reporting on it in later issues of Birdscope.
Regional Changes
Last year's Regional Scorecard showed lots of red in the East, which indicated increases in the number of birds in most eastern regions (Birdscope, Autumn 1996). This season, eastern Feeder- Watchers missed out on the irruptive winter birds. Red-breasted Nuthatches, Pine Siskins, Evening Grosbeaks, and Common Redpolls were all seen in much lower numbers throughout most of the East. Common Redpolls and Evening Grosbeaks showed the greatest declines in numbers in the northern regions, whereas Red-breasted Nuthatches and Pine Siskins also showed significant decreases in the southern and central regions, compared with last year. FeederWatchers reported increased numbers of Common Redpolls only in the Northern Rockies region, particularly in the Canadian provinces of Alberta and British Columbia (Figure 2). During the first decade of Project FeederWatch, Common Redpoll abundance has followed a biannual cycle (Figure 3), reflecting periodic invasions of the species into the East. This year, most Common Redpolls remained in the far north; participants in Alaska and northwestern Canada reported seeing flocks averaging from 9 to 13 individuals. Alaskan participants also reported a serious Salmonella outbreak that affected the Common Redpolls at their feeders. Bill Sherwonit of Anchorage wrote that "dozens, if not hundreds, of redpolls were dying by late February and early March. I cleaned up the feeders and stopped feeding for five or six weeks. I eventually did put out more seed in April, and I saw no sign of diseased birds. By then, the redpoll flocks had already started to disperse." We will be paying close attention to Common Redpoll numbers during the 1997-98 season. Among the somewhat irruptive species, American Goldfinch and Purple Finch populations remained stable when viewed on a continentwide scale, but their distribution throughout the East changed this year. Last year, American Goldfinches and Purple Finches were abundant in the Southeast region but were low in numbers in the northern and northeastern regions (Figure 4a). This year, the pattern was reversed (Figure 4b). FeederWatch has detected this synchronous movement of Purple Finches and American Goldfinches in previous years (Birdscope, Autumn 1994). Last year we reported that Sharp-shinned and Cooper's hawks were continuing to visit more and more feeders continentwide. This is true for the Cooper's Hawk again this year, but not for the Sharp-shinned Hawk. Cooper's Hawk showed a negligible change, visiting 11.02 percent of feeders this year compared with 11.13 percent last year. (Most regions actually did show declines for this species, but they were compensated for by increased sightings in the Northern Rockies, California, and Southeast regions.) The percentage of feeders visited by Sharp-shinned Hawks, however, dropped by 11 percent. This was most pronounced in the North Central region—4.67 percent of FeederWatchers observed Sharp-shinned Hawks at their feeders this year compared with 14.47 percent last year. The only areas that reported increases in this species were the same areas that reported more sightings of Cooper's Hawks—the Northern Rockies, California, and Southeast regions. By far, the most interesting FeederWatching this season took place in the West—particularly in the Southwest and Northern Rockies regions. In the late fall, information distributed through the Internet, rare bird alerts, and Audubon Field Notes suggested that Clark's Nutcrackers were moving outside their normal range. We wondered if this would mean that western FeederWatchers would have an interesting season, and we were anxious to see where Clark's Nutcrackers appeared. This species is normally not a common feeder bird anywhere—continentwide, it visits less than 1 percent of all feeders, and in the Northern Rockies, where it is most common, it visits only about 8 percent of feeders. This year, however, FeederWatchers in all western regions saw Clark's Nutcrackers, and the percentage of feeders visited in the Northern Rockies region doubled from 7.4 percent in 1995-97 to 15 percent in 1996-97. It was also a good year for seeing other corvids at western feeders. Steller's Jay and Pinyon Jay increased in numbers in nearly all western regions, appearing at twice as many feeders this year as last. The number of Mountain Chickadees seen at feeders increased in all regions where they are found. More FeederWatchers saw this species, which occurred in larger groups this year. Participants in the California and Southwest regions also saw more thrushes this year. The percentages of feeders visited by Townsend's Solitaire in the California and Southwest regions were 0.98 and 10.32, respectively, in 1995-96. This year, these percentages increased to 1.55 and 15.35 respectively. Hermit Thrush and American Robin also increased by the largest margins in California and the Southwest. Red Crossbill is a write-in species on our data form, because we don't usually receive many reports of this species. Yet, this year, Red Crossbills were reported by nearly 4 percent of FeederWatchers, with the highest proportions seen in the Southwest, Northern Rockies, and North Central regions. In Colorado, crossbills were sighted at 38.64 percent of feeders, and in South Dakota, at 33.33 percent of feeders. High percentages were also recorded in New Mexico (26.32), Wyoming (23.53), and Nebraska (23.33). Why was it such a "good" year in the West, but not in the East? One explanation could be the weather. Many parts of the East, especially the Northeast, where many FeederWatchers live, experienced mild weather and little snowfall. According to the Northeast Regional Climate Center, weather in the Northeast was cooler and wetter than normal in November, but by the end of January, the weather was unseasonably warm, and the amount of precipitation that had fallen from Maine to West Virginia was below normal. This trend of warm weather continued through February. Under these conditions, birds can easily find food in the wild and are less likely to visit feeders. Thus, good weather could keep resident birds away from feeders. But this does not explain the absence of irruptives. To understand their distribution, we need to look at seed crops. Researchers have found that Common Redpoll irruptions are tied to the availability of birch seeds—when birch seed crops fail in the North, vast numbers of redpolls move into southern regions during the winter to search for food. Western montane species also stage periodic invasions into lower altitudes and more southern latitudes. Researchers believe that these movements are triggered by food shortages (for example, seed crop failures) and abundances (for example, native fruits) in various combinations.
Rare Birds
This past season was the second year that FeederWatchers documented rare birds seen at their feeders during the FeederWatch season. We received 153 reports from 114 FeederWatchers documenting 88 different species. Some reports were of species that winter in the area but are not usually seen at feeders. Dwayne Dahlin of Winnipeg, Manitoba, observed a Merlin feeding on a bird near his feeders, and Sharon Ryther of Park Falls, Wisconsin, observed a Northern Saw-whet Owl in her yard. "It may not be a rare bird for the area, but it is rare at a feeder," she explained. Other reports, such as the Indigo Bunting that Jennifer Russell first saw at her Fayetteville, Arkansas, feeder in December or the Townsend's Warbler that stayed at Margaret DeTurk's Puyallup, Washington, feeder throughout the winter, were birds that are common summer visitors in those areas, but which should not remain throughout the winter. Still other reports, like the Brambling reported by Betsy Williams of Masset, British Columbia, and the Black-throated Gray Warbler that Edwin Sibert, Jr., saw on Martha's Vineyard, Massachusetts, documented species that were far from their normal ranges. This year—unlike last year when we received 25 reports of Northern Shrikes—no one species dominated the rare-bird reports. Only nine FeederWatchers reported seeing Northern Shrikes in 1996-97. We received five reports of Harris's Sparrows, four of Northern Goshawks, and three of Dickcissels. Most other species were reported by only one or two observers. Many of the interesting reports were accompanied by photographs or sketches, documenting truly rare or unusual birds. The ones mentioned below are just a sampling of some of the most interesting ones. I. Lehr Brisbin, Jr., of Aiken, South Carolina, videotaped two Western Tanagers. His account of this sighting, which appeared in The Axe Club News, was used to document the importance of the Hitchcock Woods, an urban forest sanctuary adjacent to his home. Several FeederWatchers reported unusual hummingbirds. Both Linda Beall, of Covington, Louisiana, and Donald Kenney, of Canotonment, Florida, saw Buff-bellied Hummingbirds, which are not often found outside Mexico and the Rio Grande Valley in Texas. This is the second year that both FeederWatchers have seen this species at their feeders. And for Donald Kenney, it is the second year he has seen the same bird. "He first arrived in November 1995 and was captured and banded," writes Mr. Kenney. "He was gone for the summer and arrived back on September 17, 1996. His band was checked and we verified that this was the same bird. When he first appeared in 1995, it was apparently the fifth sighting of this species in Florida." Marjorie G. Simons sent us photos of a Violet-crowned Hummingbird that was visiting her Tucson, Arizona, feeders. And James Wojewodski of Colden, New York, documented a Rufous Hummingbird at his feeder with a careful description and clear photos. "If it is accepted by the New York State Avian Records Committee," he writes, "it will be the first confirmed record of a Rufous Hummingbird in the western New York area." But by far the two rarest birds were a Black-throated Magpie-Jay reported by Randall Madding of Nogales, Arizona, and a Siberian Accentor reported by Poo Wright-Pulliam in Sun Valley, Idaho (see sidebar on page 5). Magpie-Jays are a Mexican species that are often sold as cage birds. The individuals that came to Randall Madding's feeders may be escaped birds that have established themselves in Arizona. These birds visited his feeders at least once a day, and often more frequently. We wish all of you an enjoyable season of winter birding as we begin our second decade of Project FeederWatch. |
