COLORADO PARKS & WILDLIFE

Attracting and holding large populations of waterfowl are goals of habitat management for nonbreeding waterfowl. Currently, many habitat planners use bioenergetics approaches to guide habitat planning for nonbreeding waterfowl and shorebirds.  In their simplest form, these bioenergetics models predict the amount of habitat needed to support a population goal based on the energy requirements of that goal and the productivity of the habitat.  Many of these models assume that energy availability is the only factor affecting duck use of sites. However, recent evidence suggests that although energy availability is important for predicting wetland use by ducks, there are many other factors that influence duck use of sites and utility of those used sites. Therefore, more complex models have been developed but it is unclear how complex these models need to be and what specific factors should be incorporated to accurately predict carrying capacity or habitat needs. Regardless of what form these models take, given the demonstrated importance of energy availability, estimates of food availability are necessary for the different wetland types in which nonbreeding ducks and shorebirds forage. Most dabbling and many diving ducks primarily consume benthic seeds during winter and migrations but transition to diets higher in invertebrates prior to nesting in spring and shorebirds primarily consume invertebrates.

 

The lower South Platte River corridor in northeastern Colorado is considered a waterfowl conservation priority area by Colorado Parks and Wildlife for migrating and wintering ducks and is important in terms of recreation. However, relatively little research has been conducted to determine the effectiveness of habitat management actions or food availability in the region. My first objective is to estimate duck and shorebird food abundance in various wetland types in the South Platte River basin throughout the nonbreeding season. Secondly, I will assess the relationship between duck and shorebird use of wetlands, food abundance, and habitat structure characteristics in an effort to inform management treatments and better understand what form the energetic habitat planning models need to take. Sampling food availability for ducks and shorebirds in wetlands is very time-intensive. Therefore, my last objective is to evaluate a rapid visual assessment procedure to estimate duck habitat quality by comparing the calculated score with actual habitat quality metrics (i.e., food availability and duck use of sites). This research will directly inform habitat conservation planning models for northeast Colorado and guide wetland habitat management to provide the greatest value to ducks and shorebirds.