BIRD COLUMN FOR FEBRUARY 6, 2005
By Benjamin P. Burtt
TOPIC: The Unusual Fall Migration of the American Tree Sparrow as Shown by the Feeder Survey
This column is divided into two sections
Section 1 discusses the migration of the tree sparrow which was discussed briefly in the bird column in the Post Standard in Syracuse on the above date.
Section 2 contains the Detailed Results for the January 2005 Feeder Survey
ANNOUNCEMENT: THE FEBRUARY FEEDER SURVEY STARTS TODAY AND ENDS SATURDAY
The Fall Migration of the American Tree Sparrow as Measured by the Feeder Survey
I have conducted a Feeder Survey in Central New York every winter for the past 47 years with the cooperation of readers of my Bird Column in the Post Standard. As the years have gone by we have learned some interesting things about the birds that spend the winter here.
During the first week of each month from October through May, readers watch their yard and count the number of birds of each species that are visible there. At the end of the week they send me a list of the species and the maximum number of each species they saw at one time during that week.
Using this information over the years we can get an idea of how the population of a given species changes over the years or even how it changes on the average through the winter from October through May.
Today, I want to tell you how I have learned something about the migration of the tree sparrow. Tree sparrows are present in Central NY from October through May, but they go far to the north in the summer to breed and then come back in the fall.
Of all the birds that are tallied on every feeder survey from October through May, it is the only one that does not breed here. It is listed on nearly half the reports in mid-winter.
It nests about 1000 miles north in the summer in the wet, brushy wastes of northern Canada. This area is north of the trees and extends as far north as there is any scrubby growth.
How do we identify it? It is the only rusty-capped sparrow that is abundant here in winter. It reminds us a bit of the chipping sparrow that also has a rusty cap and is a summer resident. However, we must remember that in the winter the chipping sparrow does NOT have a rusty cap. The top of its head at that time of year is brown with black streaks running from front to back.
In addition to its rusty cap, the tree sparrow has a dark spot in the middle of the breast and the chipping sparrow does not. On some tree sparrows that spot is not very conspicuous and this leads some observers to think it might be a chipping sparrow.
The bill of the tree sparrow is two toned, that is, the top is black and the bottom is yellow. While the chippies bill is entirely black in summer, it fades to a gray-brown in winter, but both parts of the bill are still the same color .
The tree sparrow’s nest
The nests in the far north are on the ground and hidden in dense tangles of shrubs. The tree sparrow might better be called the “brush sparrow” for it seldom spends time in trees.
Why is it called “tree” sparrow if it spends so little time in trees? The early settlers noticed that it bore a resemblance to the chestnut-capped tree sparrow of Europe and Asia which has a rusty cap, but otherwise resembles a house sparrow. A few of these European tree sparrows were released around St. Louis and you will find them in some of the field guides. In this country they are called Eurasian Tree Sparrows. Anyway, the early settlers gave it the name tree sparrow and the official name today is American Tree Sparrow.
The fall migration of the tree sparrow
This is where the feeder survey has provided some interesting information. The tree sparrow leaves that northern nesting area before September ends and starts a journey southward. A few appear here in Central New York in early October.
Figure 2 shows how the abundance of the tree sparrow changes during the winter here in Central New York. This chart is obtained from the Feeder Survey over the years.
Figure 2 In the chart, the number of tree sparrows per 100 reports is plotted on the vertical axis against the month on the horizontal axis. The number of birds for each month is the average of the counts for that month for the years from 1999 through 2003.
For example, The average of the January counts for each of those five years was 280 tree sparrows per 100 reports. For this January, 2005 it was 206. So this year the tally was a bit below the average for January.
Every year they leave their breeding grounds in the north in late September.
A few tree sparrows first appear here in early October. The numbers slowly increase here in Central New York and it takes 5 months for the numbers to reach a peak value. The numbers remain at a high level through February and March with the maximum count usually being in February.
In April, the numbers decrease as these birds start to leave for the north. By early May only a few remain, but all are gone by the end of that month.
The puzzling question is, why does it take so long for this fall migration?
Another bird that nests in the far north and migrates to the United States for the winter is the white-crowned sparrow. Its migration is more typical of the sparrow family.
The white-crowned sparrow, instead of making a leisurely migration, rushes along as do most birds and they all pass through here in October to go further south. We seldom see any during the rest of the winter. None were reported on the January survey just past.
In May the white-crowned sparrow migrates through our area on its way back to the north. This occurs in the first week of May during the last survey for the season..
I can only speculate as to why the tree sparrow migrates so slowly in the fall. It has a tiny bill and feeds on the very small seeds of grasses and weeds. Such weed seeds would not be available if the snow gets very deep. So perhaps it moves to the south only enough to find weeds that are not covered with snow.
The white-crowned sparrow is a larger bird and has a heavier bill that can crack larger seeds. I would think that it might go even more slowly than the tree sparrow since it would be able to eat tree seeds in addition to those on weeds.
Even if I can not suggest why the tree sparrow goes slowly, the Survey shows that it does. The slow migration is nothing new for in looking back over the 47 years of the feeder survey, I see the same trends.
I am a bit surprised that more people do not report tree sparrows, but I suspect that some people may be using only a hanging tubular feeder with short perches. Tree sparrows and juncos normally feed on the ground and they will not use such a feeder. In such a case they can only feed on spilled seed.
To attract those two species put out a fine seed such as cracked corn or white proso millet. Scatter it on the ground or on a large platform or tray-like feeder on a post.
THE DETAILS OF THE JANUARY FEEDER SURVEY.
The observations for the January Feeder Survey were made by readers during the first week of January.
What birds were most abundant at feeders during the first week of January when we conducted the feeder survey? While geese and crows were more abundant than any other species reported, they were not at feeders. Starlings were in third place and only some of them visit feeders regularly.
The most abundant bird right at feeders was the goldfinch. There were 837 per 100 feeders. We always present the numbers per 100 feeders so that comparisons can be made with results in the past.
The goldfinch count this year is not quite as high as last years record tally, but is way above average. In mid-winter the goldfinch has been the most abundant species at feeders in recent years.
After the goldfinch came the mourning dove, house sparrow, chickadee and junco. There were large numbers of cardinals and house finches.
It is also fun to know what species are present at most feeders. As usual, just about everyone had chickadees. 95% of the feeders had at least one. Other birds that were present at over 80% of the feeders were white-breasted nuthatches, downy woodpeckers, mourning doves and juncos. Over half the feeders had blue jays, goldfinches, titmice and hairy woodpeckers. The tree sparrow was listed by almost half the people.
A total of sixty species was spotted. Of these, 48 were fairly common, that is they were seen by 2 or more observers. The other 12 species were each seen by only one person.
The typical feeder had 13 species. By that I mean that half of the observers had more than 13 and the other half had less than 13.
The shortest lists.
The shortest list came from the New Haven Elementary School fourth grade class taught by Norma Griffin, they had 15 goldfinches and 2 mourning doves. E. Randall of Clinton tallied 4 species. In Watertown, Susan Fonday listed 5. There were 6 on the lists of Dawn Franits of Syracuse, Marsha Smith of Dryden and Mrs. William Woernley of Homer.
Tallying 7 were David Bigsby of Syracuse, Eugenia Fish of Cortland and Bob and Shirley Rock of Oswego. Cynthia Wallace had 8 in Elbridge.
The longest lists
The longest list came from Ken Smith in Groton, he had 32 species. In Waterloo, Linda Quackenbush had 31. Tallying 27 were David Pardee of Bremerton and Steve Swensen of Baldwinsville. Ken Zoller had 26 in West Winfield. Listing 25 was John and Elizabeth Wallace.
There were 22 on the lists from Paul Radway of Pompey, Steve and Dorothy Hanzlik of Whitney Point and Matt Young of DeRuyter.
Finches from the northThere are many other northern species that come down here when food is scarce in Canada. This year there has been no appreciable movement of northern finches as far south as Central New York. The northernmost survey came from Peter and Linda Biesemeyer of Malone. They did list some northern species. They had 30 redpolls, 4 pine siskins and 10 evening grosbeaks.
The Rare BirdsBirds listed by only 1 person were bufflehead by Mrs. Dana Coye at Skaneateles, a kingfisher at New Woodstock, reported by William and Marilyn Fais. Estelle Hahn of Dewitt has had a screech owl roosting in a nest box. David Pardee reported a great blue heron and a hermit thrush near Brewerton. Judy Thurber at Liverpool was the only person to report Herring gulls and Great black-backed gulls. Matt Young had a rusty blackbird at DeRuyter. Ken Zoller reported black ducks and horned larks at West Winfield.
There was one yellow-throated vireo reported, but the person did not tell how the bird was identified. This bird is normally in South America in winter and I can find no records of one here in winter. When an unusual bird is listed, it is very helpful if you give me the field marks that you used to identify the bird.
Two people reported chipping sparrows, Remember, the chipping sparrow does not have a reddish cap in winter. Most winter reports turn out to be tree sparrows.
The total pictureHere is the list of all species reported. The first figure is the number of birds spotted per 100 reports and the one in parentheses is the number of reports out of 100 that listed the species.
If you divide the number of birds by the number of reports for a particular species you get the average number visiting a feeder. It is fun to compare this with your own tally for that species.
Great blue heron 1 (1); Canada goose 2,729 (34).
Ducks: black 2 (1); mallard 21 (5); bufflehead 8 (1);
Daytime birds of prey: northern harrier 2 (2); sharp-shinned hawk 14 (14); Cooper’s hawk 19 (19); redtail 23 (19); rough-legged hawk 2 (2); pheasant 7 (4); ruffed grouse 3 (3); turkey 43 (5).
Gulls: ring-billed 21 (5); herring 2 (1); black-backed 2 (1); rock dove 129 (10); mourning dove 736 (83); screech owl 1 (1); horned owl 3 (2); kingfisher 1 (1).
Woodpeckers: red-bellied 50 (40); downy 192 (84); hairy 78 (52); flicker 4 (4); pileated 4 (4); horned lark 1 (1); blue jay 247 (67); crow 2,018 (84); raven 11 (5); chickadee 516 (95); titmouse 148 (64); red-breasted nuthatch 44 (32); white-breasted nuthatch 143 (85); brown creeper 4 (4); Carolina wren 4 (4); bluebird 11 (2); hermit thrush 1 (1); robin 72 (7); cedar waxwing 133 (8); northern shrike 2 (2); starling 941 (35); cardinal 355 (82).
Sparrows: tree 206 (44); chipping 4 (2); song 4 (3); white-throated 48 (16); junco 434 (79); red-winged blackbird 4 (2); rusty blackbird 1 (1); grackle 4 (3); cowbird 64 (7); purple finch 109(17); house finch 310 (41); redpoll 134 (8); pine siskin 5 (2); goldfinch 857 (67); evening grosbeak 10(1); house sparrow 667 (44).
Announcement: The February Feeder Survey starts today, February 6