Hay-Zama Lakes Duck Breeding and Molting Population Density Surveys, 2005 - 2007
Ken D. Wright and Ryan Hermanutz
The Hay-Zama Lakes complex is widely recognized as an important waterfowl staging area, however little information exists regarding the importance of this unique wetland area for breeding and molting waterfowl. Waterfowl management in this area has focused on monitoring staging waterfowl numbers near the numerous producing oil and gas well sites within the wetland complex since 1978. Ongoing monitoring is expected to continue until oil and gas activity is phased out between 2012 and 2017. The purpose of this survey was to provide stakeholders with additional waterfowl population data for consideration in managing this complex as new economic values develop. Our objectives were to estimate waterfowl population density in the Hay- Zama complex during breeding and molting seasons over a three-year period, and to identify and characterize areas within the complex with the greatest densities.
We flew a series of aerial surveys over a three-year period during breeding and molting seasons. Four surveys were flown each year; one in late May and one in early June for the breeding season, and one in late July and one in early August for the molting season. Waterfowl observed were grouped into social classes to estimate breeding density, and total numbers observed were used to calculate molting densities. Social classes are a tool developed for calculating densities during the breeding period and are not applicable during the molting season.
Breeding densities of all species combined (indicated breeding birds per hectare (IBB/ha)) ranged from 0.511 to 1.179 and molting densities from 0.916 to 2.454 birds/ha over the three-year survey period. Greatest densities of breeding birds were found on the north and east portions of the complex, whereas greatest densities of molting birds were observed in the center of the complex.