Specimen of the Month: Mapping Vagrancy

American Purple Gallinules, clad in vivid, tropical purples, greens, and bright yellow as adults, lurk among the floating vegetation of Gulf region wetlands with the strong legs of a typical rail. Regarding this species, the famed ornithologist John James Audubon once observed, "the Purple Gallinule is a constant resident in the United States, although peculiar to our southern districts, where I have met with it at all seasons." He went on to assure readers that "it never, I believe, ascends the Mississippi beyond Memphis." Yet a new Museum specimen holds the story of a journey far beyond what Audubon, and probably the rest of us, would have thought to observe. 

Thick legs and long toes help this species to
effortlessly walk on top of lily pads in its wetland habitats.

On display this month, an immature representative of this species (Porphyrio martinica) came to the Museum as salvaged remains. This bird arrived as unexpectedly as most other deposits which we regularly accept from members of the public. Remains show up and after a few standard questions, I generally accept them--but not always. Not every dead songbird can fit in our collection, and not every natural object serves our mission of connecting people to Northwoods nature. When a man arrived in the lobby with a plastic zip-lock this year, I intended to decline the frozen Gulf bird held inside. After some inquiry though, I found that the bird had visited and then drowned in nearby Duluth--a rare yet seemingly natural occurrence. 

Even though this juvenile exhibits some vivid color,
the adults are much more vibrant with a bright bill
and forehead shield to compliment brilliant purple feathers. 

Purple gallinules are known vagrants. According to documented observations spanning the last few decades, individuals have been found far north to Canada and Iceland, and as far south as South Georgia Island. A peek at online birding checklists reveals an array of observation reports from citizens throughout the Americas and even mainland Europe. These wayward travels have become accepted occurrences, but there's still plenty of room for further inquiry. 

Decades ago, an influx of purple gallinules turning up in Wisconsin left some wondering whether this behavior correlated with environmental causes, such as  heightened spring flooding along the Mississippi. Over the years, atypical movement far outside the purple gallinule range has seemingly increased. Global bird monitoring projects have helped to compile observation reports, and in turn will hopefully provide better insight into how environmental conditions may affect vagrancy. What is the hypothesis so far? It is likely that recently warmer summers and drier winters along the Gulf could lead to increased winter vagrancy for the purple gallinule. Since Audubon's time, environmental changes have certainly occurred.  

Is this why our specimen was found trapped along the icy banks of the St. Louis River? Perhaps--what is certain is that preserving the salvaged remains may allow for future inquiry into this individual's life history. It makes for a rather beautiful Specimen of the Month, too.