Western (Aechmophorus occidentalis) and eared (Podiceps nigricollis) grebes of central Alberta : 2002 field summary /

Abstract

EXECUTIVE SUMMARYThis project is in its second year, and is designed to monitor population trends and reproductive success of western grebes (Aechmophorus occidentalis) and eared grebes ( Podiceps nigricollis) within the Stony Plain study area, Alberta. Surveys are projected to span a five year period, and the results will be used in conservation and management efforts. This project also provides information to support lake habitat conservation and public education. Survey protocols developed by this project are applicable to other regions in Alberta. In 2002, surveying effort was focused on the primary western and eared grebe populations identified in the initial year of this project. Ground nest surveys were the primary means used to estimate adult population sizes; however, this technique was modified slightly from 2001. Instead of conducting a single total nest count at the predicted peak of the nesting season, we surveyed each colony along a sample transect several times during the nesting season. Total nest counts were conducted near end or after the nesting period, and the results from which were used to derive a total breeding adult population estimate.

Western (Aechmophorus occidentalis) and eared (Podiceps nigricollis) grebes of central Alberta : 2004 field summary /

“…The regional eared grebe population in 2004 was 8858, almost 5 times greater than in 2003 ( Figure 2), but similar to 2001 and 2002 (Hanus et al 2002a, b, Hanus et al 2003). If eared grebes from the newly discovered Majeau Lake colony are exempt, the revised estimate is approximately 5264 adults, which is still higher than 2003, but lower than 2001 and 2002 estimates (Figure 2).…”

“…As an example, a proposed housing development adjacent to the western grebe colony on Lac Ste Anne has the potential to negatively impact nesting grebes by reducing and fragmenting nesting habitat, and increasing human presence and associated disturbances, including powerboats, dogs, and even corvids. Based on complete shoreline surveys for emergent vegetation habitat in 2002, the colony is located within the largest and most intact section of bulrush habitat remaining on the lake (Hanus et al 2002a). Stringent mitigation measures are required to protect the colony, although the success of such measures is uncertain given the projected increase in human activity.…”

“…The information presented in this report represents the findings from the fourth year of surveying western and eared grebes within the Stony Plain study area in Alberta (Appendix 1), with comparisons to data from previous years of the study. Baseline data for this area for 2001 to 2003 are presented in Hanus et al (2002aHanus et al ( , 2002bHanus et al ( , 2003. A synthesis of provincial data for western and eared grebes is provided in Hanus (2002).…”

Western (Aechmophorus occidentalis) grebes in Alberta : 2006 field summary /

“…The information in this report represents the findings from the sixth year of surveying western grebes within what was referred to in previous reports as the "Stony Plain Study Area". Previous data from the Stony Plain study area for 2001 to 2005 are found in Hanus et al (2002aHanus et al ( , 2002bHanus et al ( , 2003, Berg et al (2004), and Berg and Wollis (2005, unpublished report). While western grebe data in the other areas have been previously reported (Hanneman and Heckbert 2001 ;Found and Hubbs 2004), this is the first year in which western grebe data from all study regions in Alberta are compiled into one document.…”

“…Western grebes (.Aechmophorus occidentalis) are widely distributed across western and central North America, with some colonies numbering into the thousands (Hanus et al 2002a). These colonial-nesting waterbirds build precarious nests of soft vegetation that are either entirely freefloating, or secured to emergent vegetation (Storer and Nuechterlein 1992).…”