Pine Siskin Irruption 2008-2009
 
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Pine Siskins are making a dramatic showing at feeders this winter. We have been hearing from FeederWatch participants like Marion Kinney of Somerville, New Jersey, and Kaye Johnson of Sperryville, Virginia, who have Pine Siskins at their feeders for the first time. Other participants are seeing unusually large flocks of these birds. Shirley Robinson of Rhinelander, Wisconsin, wrote, “Pine Siskins were everywhere. I have so many this winter, I have been filling my five thistle sacks every day.” For many participants, the siskins are quickly consuming large amounts of birdseed and, where particularly large flocks are involved, driving other birds away from the feeders. Pine Siskins are an irruptive species, which means that these birds move in irregular patterns in winter.
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Photo by David Smith of Grand Junction, Colorado |
Although siskins can be found in most parts of the U.S. and Canada any winter, they are visiting a higher proportion of feeders during the 2008-09 winter and their flock sizes are larger. |
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We recently conducted a preliminary analysis to compare siskin numbers during the current winter with reports from 2007-08. Data submitted online through February 15, 2009 were compared with the same time period last winter. During the 2007-08 winter, Pine Siskins were reported at 24.4% of Project FeederWatch sites continent-wide, and during the 2008-09 winter, they visited 50% of sites. The average flock size during the 2007-08 winter was 11.7, and it was 15 during 2008-09. |
| Photo by Rachel Banai of Teaneck, New Jersey |
If you draw a line from Thunderbay, Ontario, south to New Orleans, Louisiana, Pine Siskin numbers to the east changed even more dramatically between last winter and this winter. Pine Siskins were reported at 18.6% of feeders in the east during 2007-08 and at 49.6% of sites in 2008-09. The flock size increased dramatically as well with an average flock size of 7.2 during the 2007-08 and 15.5 this past winter.
Pine Siskins typically irrupt in the west every other winter, but the pattern is much less reliable in the east. Siskins routinely visit feeders in the mountainous west in large numbers and only show minimal irruption patterns there. The large numbers of siskins in the east this winter are most likely due to a shortage of their typical winter food supplies in the forests of Canada.
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See where FeederWatch participants are reporting siskins this winter and compare to past winters in the Explore Data section of this web site. |
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Photo by David Smith of Grand Junction, Colorado |
 Identifying Pine Siskins
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When seeing Pine Siskins for the first time, they can be hard to identify. Sometimes they mix with a flock of American Goldfinches, which are similar in size, shape, and behavior, making them hard to notice unless you look closely. When seen alone, they look very much like female House Finches. Pine Siskins have brown streaks like House Finches, but they are smaller and have small bills. Pine Siskins also have a touch of yellow in their wings, but that can be hard to see, especially at a distance.
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| Photo by David Smith of Grand Junction, Colorado |
| Brighter individuals have more yellow, and when siskins spread their wings and tail, the yellow is more easily seen. You can learn more about Pine Siskins on the Lab’s All About Birds web site. |
Salmonella outbreaks
As often happens in birds that feed and roost in tight flocks, there have been outbreaks of Salmonella reported in some Pine Siskin flocks. Salmonellosis is caused by a bacteria belonging to the genus Salmonella. It is a common cause of mortality in feeder birds, but the symptoms are not always obvious. Sick birds may appear thin, fluffed up, and may have swollen eyelids. They are often lethargic and easy to approach. Some infected birds may show no outward symptoms but are carriers of the disease and can spread the infection to other birds.
Salmonellosis is primarily transmitted by fecal contamination of food and water by sick birds, though it can also be transmitted by bird-to-bird contact. Occasionally, outbreaks of the disease cause significant mortality in certain species.
If a sick bird comes to your feeder, minimize the risk of infecting other birds by cleaning your feeder area thoroughly. If you see several diseased birds, take down all your feeders for at least a week to give the birds a chance to disperse. Salmonella strains found in birds can be dangerous to humans, so do not handle any sick or dead birds, and be sure to wash your hands thoroughly after handling feeders.
Project FeederWatch participants can report sick birds observed during the FeederWatch season to Project FeederWatch using the Sick Bird Form found from the last main link on the Data Entry page or by sending a note with their paper data booklet at the end of the season.
For more information on diseases affecting wild birds, contact the National Wildlife Health Center in the U.S. or the Canadian Cooperative Wildlife Health Centre in Canada. |
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