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An Exceptional Story About Routine Data from the House Finch Disease Survey

by Melanie Driscoll

For nearly seven years, John Merchant has been watching finches at his feeders in Eagle, Colorado, and has submitted his observations, month after month, to the Cornell Lab of Ornithology’s House Finch Disease Survey. In all that time, none of the birds at his feeders have shown signs of House Finch eye disease, a sometimes-lethal bacterial infection that has spread rapidly across the continent since 1994, when the first sick finches were found near Washington, D.C.

a healthy house finch

What makes Merchant’s contribution extraordinary is his faithful participation in the House Finch Disease Survey even though he has always had only “null data” to report—that is, the absence of diseased birds. Participants often feel more motivated to send in unusual or interesting data. Who among us wouldn’t feel more excited about recording that we’ve seen a flock of Common Redpolls during a FeederWatch count than no birds at all, or feel that a sighting of a sick bird might be more valuable than the usual reports of healthy ones?

In fact, null data are essential for an accurate understanding of any scientific question, including the spread and impact of House Finch eye disease. Thanks to John Merchant and thousands of other participants, the House Finch Disease Survey has tracked when the disease crossed the Rocky Mountains and how it has affected House Finches throughout the western United States and western Canada—a pattern that never could have been confirmed if people had only reported sick birds.

Merchant is also an exceptional participant because he submits data throughout the summer months. Even though the House Finch Disease Survey is a year-round project, many participants send data only from November through April, the same months when they participate in Project FeederWatch. When the FeederWatch season ends each year, Merchant continues sending us House Finch data, averaging 28 observation days per month, and filling important gaps in our seasonal records.

The more data that participants send in regularly, through all seasons of the year, regardless of the presence or absence of House Finch eye disease, the greater our understanding will be about how the disease cycles. We thank all of our participants for helping us document these patterns of disease and population flux, and we encourage everyone with finches at their feeders to join the project—see House Finch Disease Survey.

Melanie Driscoll, project coordinator, House Finch Disease Survey

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