The Canadian Field-Naturalist (E-Journal)
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Dan Brunton steps down from the Ottawa Field Naturalists’ Club Publications Committee after many years of service
Draft Minutes of the 142nd Annual Business Meeting (ABM) of the Ottawa Field-Naturalists’ Club, 12 January 2021
Timing of pair formation and male acquisition of alternate plumage by three wintering dabbling ducks
Pair formation in ducks is thought to be influenced by the acquisition of breeding plumage, the occurrence of courtship display, or both. We examined the frequency of pair formation in Mallard (Anas platyrhynchos), Green-winged Teal (Anas crecca carolinensis), and Northern Shoveler (Spatula clypeata) in the central valley of California in relation to the frequencies of male attainment of breeding plumage and courtship display. Predictions related to two hypotheses are: (1) the timing of pair formation is directly related to the attainment of breeding (definitive alternate) plumage by males, and (2) frequencies of courtship display are highest during pair formation. Most female Mallard were paired by the end of October, with >80% in pairs by early December. Of Northern Shoveler, 90% were paired by early January and 90% of female Green-winged Teal were paired by early February. The highest rates of courtship display by Mallard were observed during October through November, by Northern Shoveler in November, and by Green-winged Teal in November through January. Courtship display was, therefore, relatively frequent at the same time as pair formation for all three species. Northern Shoveler spent less time in courtship display than the other two species. Most (90%) male Mallard had acquired alternate plumage by mid-November, Northern Shoveler by early February, and Green-winged Teal by mid-December. Thus, timing of pair formation coincided with timing of attainment of breeding plumage in Mallard and Green-winged Teal but not Northern Shoveler
Banded Killifish (Fundulus diaphanus) and Mummichog (Fundulus heteroclitus) distributions in insular Newfoundland waters: implications for a Species at Risk
Newfoundland’s Banded Killifish (Fundulus diaphanus) population is listed as a species of Special Concern under Canada’s Species at Risk Act and Vulnerable under Newfoundland and Labrador’s Endangered Species Act. Mummichog (Fundulus heteroclitus) is a similar looking fish species and is currently under review by Newfoundland and Labrador’s Species Status Advisory Committee. Both species have limited known distributions in Newfoundland waters that overlap. They may occur sympatrically in estuaries and occasionally hybridize; thus, field identifications can be challenging. We found that dorsal fin position and caudal fin depth were the most useful morphological characters for distinguishing Banded Killifish and Mummichog in the field. We used local ecological knowledge, literature review, museum records, and field surveys to update the known distribution ranges and found both species in more locations than previously documented in Newfoundland. Thus, we extend their known ranges. Our results will be critical in future status assessments of these species in Newfoundland