Unusual weather events like the frequent and heavy rainfall we have experienced for the last month and a half are bound to affect local wildlife populations. While I cannot say for sure how it has affected the local bird population, I do know that it has affected one particular species: the prothonotary warbler.
All living things, including plants, develop strategies for survival. Prothonotary warblers have developed the habit of nesting in hollows, cavities and crevices in trees. They will readily use nest boxes if they are erected in appropriate habitat. Of the 38 species of warblers that occur in the Carolinas at least some portion of the year, the prothonotary is the only one to employ this strategy. They are extremely common in the Southeastern swamps and river and creek bottoms, indicating that this is very successful strategy for them to use. In Mecklenburg and surrounding counties, they are not as common but can still be found easily along the Catawba River and along the major creek systems.
The prothonotaries also show a preference for choosing nesting cavities that are directly over water, sometimes very low over the water. If fledged young plop into the water on their maiden flights, they are able to swim to safety, another unique adaptation.
The species is considered to be a rare breeder in Mecklenburg County, so county Natural Resources staff along with volunteers from Mecklenburg Audubon have erected and monitored nest boxes for them in some nature preserves. The program has been very successful, but this year the strategies backfired. Flooding and high water levels in the Catawba’s coves put the nest boxes under water twice. Volunteers conducting monitoring checks found adult birds and chicks drowned in the boxes. Normally the monitored boxes produce two nestings and around five to eight fledglings each year; this year there will be none.
So it has been a poor season for reproductive success for the prothonotaries, at least in some areas. To me this illustrates how unique strategies for survival often leave little margin for error; how one environmental factor that deviates from the norm can have a profound effect, long or short term, on vulnerable species.
Taylor Piephoff is a local naturalist with an interest in the birds and wildlife of the southern Piedmont: PiephoffT@aol.com.
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