Parasitic Jaeger in St. Louis County
2011-10-05

'Rare Regular' in Minnesota

While driving Minnesota Avenue near Sky Harbor Airport on Park Point, I was surprised to see a juvenile Parasitic Jaeger (Stercorarius parasiticus) flying over the sand dunes lining the beach at the Park Point Recreation Area, Duluth, 5 October 2011. Its smaller size and wingspan in direct comparison to multiple Ring-billed Gulls were noted during its acrobatic pursuits along the beach. Identification criteria visible in these images include its relatively narrow, pencil-shaped, dark-tipped bill (heavier and larger at the gonys with a prominent hook on pomarinus, shorter with proportionately more of the bill dark on longicaudus); triangular head shape (larger head with more prominent forehead on pomarinus); cinnamon-buff hindnape (paler nape normally not seen on juvenile pomarinus); rusty tones on underwing bars making the underwings about the same shade as the underbody (underwings typically paler than body on juvenile pomarinus and longicaudus); indistinct barring on under tail-coverts (normally thickly and distinctly barred on juvenile pomarinus); and sharply pointed central pair of rectrices (broader and thumb-shaped on juvenile pomarinus). Like many juvenile Parasitics, this individual shows a subtle pale flash on the underwing primary coverts, but this is neither as extensive nor as obvious as what would be expected on juvenile pomarinus (which typically shows a "double underwing flash" even when seen at long distance). All of the images used to create this composite image were taken in Minnesota at approximately 4:20 PM when the bird was illuminated by the late afternoon sun shining behind the photographer. This same bird was seen and photographed by myself and other observers throughout the morning hours at parking lot #1 on Wisconsin Point, furnishing further photographic evidence that individual jaegers may be seen at both locations.

Peder H. Svingen