Allerton

Park & Retreat Center

Northern Saw-Whet Owl Survey

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Last month, our Natural Areas staff helped University of Illinois Urbana-Champaign biologists and Illinois Natural History Survey conduct a Northern Saw-Whet Owl survey. They were fortunate to net two and attached a numbered identification band to their legs that will allow other researchers who capture them to identify where these migratory owls have been. Owls are weighed, measured, sexed and aged and then quickly released. The two Allerton visitors were both females – one hatched in 2021 and one hatched in 2020.

Biologist Michael Avara from the University of Illinois Avian Lab removes a White-Throated Sparrow from the mist net, which are used to catch birds for research purposes. The nets are a very fine mesh almost invisible when expanded.

Owls are fitted with a light-weight aluminum band. In the event they are recaptured valuable migration data can be collected.

Biologists take a variety of measurements to help determine the sex, age and health of the owls.

Owls incorporate pigments known as porphyrins in their feathers. These pigments fluoresce under UV light but degrade over time. This degrading process helps the biologists determine which feathers are new and which are old. This technique is used to age the owls. This owl was hatched in 2020.

Northern Saw-Whet Owl

Northern Saw-Whet Owl caught near the Allerton Mansion poses near a photo of the Mansion.

 

Learn more about research going on in Allerton’s Natural Areas here.