PEARL

Chimney swifts (Chaetura pelagica) in flight have cigar-shaped bodies attached to swept-back wings. Note the spine-tipped tails. Swifts catch flying insects at altitudes higher on average than other insect eating birds like swallows and flycatchers. Credit: Mike Veltri.

Chimney swift roosting inside a domestic chimney used as a nest site (note, not from the Fleming hall chimney). Swifts cling to the vertical wall with short legs and long claws, propping their spine-tipped tails against the wall below them. Credit: Bruce Di Labio.

Built in 1904, Fleming Hall contained the central heating plant for campus until it was decommissioned in 1927. After a fire in 1933 the building and chimney were rebuilt. It remained open to roosting swifts until about 1993 when it was screened off to exclude the birds. Credit: Chris Grooms, Queen's University.

Built in 1904, Fleming Hall contained the central heating plant for campus until it was decommissioned in 1927. After a fire in 1933 the building and chimney were rebuilt. It remained open to roosting swifts until about 1993 when it was screened off to exclude the birds. Credit: Chris Grooms, Queen's University.

Swifts' eye view down the ~1m cross-section of the octagonal opening of Fleming Hall chimney. Birds roost on the inside walls of the chimney. Credit: Chris Grooms, Queen's University.

After excavating into the chimney and up through the guano deposit, samples were taken from the face of the deposit carved out like a soil test pit. A 1cm high stainless steel tray was used to "peel" off each layer. Protective breathing gear was used against dust and pathogens. The work was done before swifts returned from migration. Credit: Chris Grooms, Queen's University.