Southern Montana Looking Better Than Last Year
Since our last post we have flown a few thousand more miles of transects across Montana. As ground crew leader Pam Garrettson noted in one of her earlier posts, southern Montana does not naturally contain a great deal of waterfowl habitat. That said, the conditions are improved over what we observed last year. One shortcoming of many of the wetlands in Montana is the lack of cover around the edges, due to farming practices or intense cattle use. Upland nesting species such as the northern pintail can be directly affected due to lack of vegetation along the wetland edge. In biological studies, researchers found that pintails select nesting sites in proportion to habitat availability. For example, if 50% of the wetland habitats in a given area were in agriculture stubble with no edge cover, and 50% were natural wetlands with better edge habitat, northern pintail nests would be distributed in approximately the same 50:50 split. Mallards, on the other hand, have been observed selecting for better nesting cover. So, using the same mixture of habitats mentioned above, maybe 70% of the mallards would nest in the better habitat area, with only 30% nesting in the agriculture stubble. Cover is one of the main variables influencing rates of predation, and hence, those nests found in stubble field wetlands could experience higher predation. Researchers hypothesize that is one reason why northern pintails did not respond to the improved prairie habitat conditions of the 1990s, while mallards, on the other hand, did respond favorably to the improved conditions.