Bonaparte's Gull with full hood on 10 December 2005

Niagara River at Fort Erie, Ontario


Scroll down for 7 photos. Text by Ron Pittaway and Jean Iron.

Figure 1. Bonaparte's Gull in definitive alternate plumage with full hood. The bright orange-red legs suggest advanced alternate plumage as most birds in definitive basic plumage had duller legs. See other feathers below which support an advanced prealternate molt rather than retained alternate plumage.


Figure 2. The white tipped black primaries are fresh indicting recent prebasic molt. Mixture of new and old (frayed) scapulars and many older and frayed wing coverts suggest incomplete prebasic molt.


Figure 3. Mixture of worn and fresh feathering suggesting an incomplete definitive prebasic molt. Tertials and upper scapulars are fresh.


Figure 4.


Figure 5. Whiter nape and back of neck typical of alternate plumage. Gray nape in basic plumage.


Figures 6 and 7. Carmine red orbital ring (normally black) is unusual in definitive alternate birds, but BNA Account # 634 says there is a narrow carmine orbital ring in first alternate birds. This suggests that orbital ring color needs more study as carmine orbital rings may occur at low frequencies in other age classes. A hormone imbalance may be responsible for the early onset of definitive alternate plumage and carmine orbital ring color in this individual.