Sampling Tree Swallow Blood on Sudbury River

Part of the Sudbury River Superfund Site. Refuge sign floating near boat launch. Meri checking a bird box for inhabitants. Mike trudging through the marsh. Swallow sitting on a bird box. A bird in hand Mike and Meri work together to complete field sampling. Mike taking a blood sample from a swallow Mike and Meri baging a feather sample Herring taking flight.