An anomalous northern saw-whet owl (Aegolius acadicus) egg

Abstract

An anomalously large and coloured egg was found within a clutch of the Northern Saw-whet Owl (Aegolius acadicus) in Nova Scotia; all other eggs of the clutch were within the normal size and colour range for the species. Analysis of three mitochondrial genes suggests all eggs in the clutch were laid by Northern Saw-whet Owl(s) with similar genetic make-up. This is the first report of an anomalous egg from this species, and a rare example of added pigment.