Mining for Melanerpes
Our Woodpecker Cavity Cam project is in full swing! Over the last month, more than 1500 volunteers have made hundreds of thousands of classifications of trail camera videos. The cameras are still up and running at several nest trees, and our field team replaced SD cards in them this week. Siah St. Clair, our camera supervolunteer, took a brief glance through the cards and came across a couple of gems. We don’t have these videos up on the classification project quite yet, but just couldn’t wait to share them with you! As you’ll note from the date in the top corner of the videos (6/16/2021), these are truly hot off the press.
First up, nest 258 - home of red-headed woodpeckers Markie (the female) and UB (the unbanded male). It is a dark, humid night after another hot day during our latest heatwave. UB is on nighttime nest duty and all is peaceful. Then suddenly around 4:19am, the tree he and his nestlings are living in begins to shake! The video captures UB as he sticks his head out of the cavity opening in a classic vigilant posture, a reaction to the noise and movement of the tree. He sinks back down into the nest to protect the nestlings, and a moment later, a raccoon snout appears on the video! A damp and bedraggled - and no doubt hungry - raccoon comes into full view. Over the next several minutes, the raccoon tries to access the nest and the meal it contains. The camera captures the raccoon reaching in with its left arm, then climbing up higher and attempting to reach down from above with its right arm. After four videos of attempted entry, the raccoon leaves empty-handed. Another win for the red-headed woodpecker!
Raccoons are a common sight at Cedar Creek, on the ground and on fallen trees in our natural areas, leaving tracks near our main buildings, and climbing up trees in search of meals. Raccoons are intelligent, curious generalist omnivores. They will opportunistically eat eggs, berries, birds, insects, nuts, and pretty much anything else they can get their dexterous hands on. Red-headed woodpeckers keep their eggs and young safe from raccoons in a couple of ways. One is behavioral, which is on display in this video. The adult on guard duty is vigilant and protective, using their body and beak to protect the young. A second strategy is more structural. A cross-section of a red-headed woodpecker cavity shows that it is pear-shaped, with a narrow entry hole that is perpendicular to the actual cavity. This design makes it extremely challenging for a raccoon to stick their arm all the way to the bottom of the nest, particularly with an angry adult inside!
A few hours earlier on the same night, there was another predation attempt. This one took place at nest 255, home to a pair of red-headed woodpeckers named Tomek and Iza. At the time this video was taken, the woodpecker pair had several nestlings present in the cavity. This video captures a less common mammal of the oak savanna - a fisher! From the size of the fisher relative to the cavity opening, it is most likely a female fisher. She tries to access the cavity with her snout, then her paw, then her snout again before eventually giving up and like the raccoon, leaving empty-handed. Part way through the video, she turns to give the camera a stunning shot of her face! Another predator foiled by good cavity design.
Fishers are the largest weasel that breeds in Minnesota. Despite their name, they aren’t particularly interested in or talented at fishing, but instead specialize in tree climbing (check out the large, thick claws on the fisher in the video). They are one of the few predatory mammals that is adept enough to take down arboreal prey like porcupines. Fishers have specially-adapted hind legs that can rotate 180° to allow them to climb down trees head-first, even while carrying heavy loads like kits or prey that can weigh up to 25% of their body weight. Impressive! Although fishers tend to be solitary and secretive, we know from other work at Cedar Creek that they are present throughout the reserve in what appears to be a decently high density. We regularly find their tracks on the sand roads at Cedar Creek, and also capture them on trail cameras mounted only 3 feet off the ground for a different research project. This video is our first confirmed fisher visiting a red-headed woodpecker nest though!
The fisher video brings our list of species caught on these nest cavity cameras to 28 - an incredible array of birds, mammals, amphibians and insects. This latest round of camera checks has shown that there is still so much to learn about life at these cavities. We can’t wait to get this latest round of images up at http://z.umn.edu/woodpeckercams for our volunteer community to investigate! Maybe you’ll get lucky and find a 29th species to add to our list!