. The Canadian field-naturalist. 258 The Canadian Field-Naturalist Vol. 99. Figure 1. Southampton Island, showing the position of the colony visited (C) clear yellow irides. The wing-tips of Kumlien's Gulls are never darker than medium grey. In both species the eye-ring is normally reddish-purple. In the course of seabird colony surveys around Southampton Island in June 1983 we located a mixed colony of Thayer's and Kumlien's Gulls on the north- east coast of the Bell Peninsula (Figure 1). That col- ony was not visited by Smith. We visited the colony on the ground on 29 June and estimated that
. The Canadian field-naturalist. 258 The Canadian Field-Naturalist Vol. 99. Figure 1. Southampton Island, showing the position of the colony visited (C) clear yellow irides. The wing-tips of Kumlien's Gulls are never darker than medium grey. In both species the eye-ring is normally reddish-purple. In the course of seabird colony surveys around Southampton Island in June 1983 we located a mixed colony of Thayer's and Kumlien's Gulls on the north- east coast of the Bell Peninsula (Figure 1). That col- ony was not visited by Smith. We visited the colony on the ground on 29 June and estimated that 90-100 birds were present, many of which were incubating. The nests were situated on cliffs about 80 m high, facing seaward, but we were able to climb close to the colony and examine birds through binoculars at ranges down to 10 m. We made field notes of plumage and soft parts for all individuals we could see clearly and recorded where courtship or greeting behaviour suggested that birds were paired. Plumages exhibited among birds seen well ranged from typical Thayer's, with blackish tips to the pri- maries, enclosing prominent white windows, to typi- cal Kumlien's, with virtually unmarked tips to the primaries, merely faint traces of pale brown on the outer web. At least two individuals appeared inter- mediate, with medium brown markings on the primar- ies distributed in exactly the same fashion as the typi- cal Thayer's. The pattern on the primary feathers was recorded for 43 birds, of which 25 (58%) appeared typical Thayer's and 16 (37%) typical Kumlien's. All the birds present had dark eye-rings. Some had dark (presumably purple, Smith 1969) irides, while others had yellow irides and some appeared inter- mediate. No correlation was apparent between the colour of the primaries and the irides; birds with both Thayer's and Kumlien's wing patterns had yellow and dark irides. The two intermediate birds both had dark irides, as did 18 out of 24(75%) birds seen adequately. Plumag
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