Reproductive potential in parkland- and arctic-nesting populations of mallards and pintails (Anatidae)

• Published in: Canadian Journal of Zoology
• Main Authors: Calverley, B. K., Boag, D. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1977
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Arctic; Mackenzie River; Parkland; Mackenzie river
• Online Access: http://dx.doi.org/10.1139/z77-163; http://www.nrcresearchpress.com/doi/pdf/10.1139/z77-163

We estimated the reproductive potential of mallards (Anas platyrhynchos) and pintails (A. acuta) nesting in the parklands of Alberta and the delta of the Mackenzie River, N.W.T., by recording the number of laying females and the potential clutch size, based on the status of ovarian follicles, in samples of each species collected at the two latitudes. A larger proportion of the ducks collected in the parklands were laying and their potential clutch sizes were larger than in the arctic. Thus, both species exhibited a greater reproductive potential in the parklands than in the arctic. The reasons for these differences are discussed in relation to energy costs to ducks breeding at the two latitudes.