Blackpoll Warbler - Dendroica striata
July 08, 2008
Last week at the museum, one of my specimens was a male Blackpoll warbler. Dave handed it to me with an apologetic wince: it was extraordinarily fat. Dave stated normal weight for a spring Blackpoll was around 12 -13 grams, but this fellow logged in as 17. No big shakes for a species of our size, but for this tiny fellow, that's a huge difference. Birds with large amounts of fat can pose a bit of challenge to creating a clean, and neat study skin. As much fat as possible must be removed from tissue, otherwise, its oils will soil the feathers, discoloring the specimen over time. Despite the amount of fat that had to be removed, my specimen turned out relatively clean.
As I was finishing up for the day John Bates, Zoology Chairman and Associate Curator of Birds, wandered into the prep lab and said "Oh a Blackpoll! Do you know about these?". My blank stare encouraged him to lead us to the zoology office, where he swiped a rather faded world globe from the desk. The globe had worn out areas on it, presumably as a result of just what John proceeded to do. He pressed his forefinger into Alaska, stating Dendroica striata bred there and throughout the boreal belt line. He then dragged his finger down to North Carolina and paused. He explained, while proceeding to drag his finger down to Venezuela, that there is evidence that Blackpolls on their way back south pause in North Carolina and other areas of New England. They gorge themselves and double their body mass before making an extraordinary 3000k, 88hr nonstop flight over water to their wintering grounds in northern South America. There is no evidence that the little birds stop on any islands along their herculean ocean trek. Somehow, by John using a physical globe to illustrate the migration path and length, it was made more impressive than if he had pulled up Google Earth.
Following up at home, I found data stating Blackpoll non-fat weights ranging from 8 to 11 grams, and their fueled up state tipping the scales at roughly 22 grams. My 17 gram fellow, being a spring bird, was on his way north to a boreal breeding ground. Poor fellow, he had crossed oceans with energy to spare, only to smack into a downtown window. On the brighter side, what I love most about volunteering at the museum is having a brief conversation such as the one above that will forever illuminate a previously unfamiliar species, and spark again my utter awe and wonder at the natural world. At the very least I was inspired to get a globe for the home studio. I opted for raised relief, and "natural" coloring; no pink and purple countries for me. I stuck with the home town team: Chicago's own Replogle.
*painting is in Etsy shop.