I have been looking everywhere for signs of spring! Although this has not been a terribly hard winter (here in Western Pennsylvania, anyway), everyone is justifiably sick of the cold temperatures and the gray skies. Also, most of us desperately miss the color green and the morning choruses of the waking birds and the evening trilling of the peepers and tree frogs! We are ready for spring to arrive!
My cat Mazie (pictured above) has decided that we will have more winter this year, though. She fled from the front yard to the porch and ran all the way to the basement when we did our fifth annual House Cat Day experiment!
The three of the first four “Signs of Spring” I have seen are not terribly welcome ones. I guess we have to take what we can get! I’ll start with the “nice” one and then get all dark and gloomy.
The bees are awake and “afoot!” On a warm afternoon last week a squadron of honeybees converged on my bird feeders in search of anything sweet and edible! I think that the powdery residue of the shelled corn that I have been putting out for the jays, crows, and squirrels drew the bees in (and hopefully gave them something that they could take back to their hive). The photo on the left shows one of the honey bees checking out the sunflower seeds! It is not energetically beneficial for the bees to go out foraging before there are any flowers, but it was nice to see them after all of these bee-less winter months!
A second sign of spring was inside my home: over the past few weeks the distinctive aroma of brown marmorated stink bugs has been rising in unexpected places throughout my house. When we were sitting in the living room in the evening, when I was riding my exercise bicycle in the afternoon, when we were getting ready to feed our dog her dinner, all of a sudden our olfactory senses were overwhelmed by the pungent scent of a stink bug (or three, or four). The bugs were stuck away and hiding in all sorts of nooks and crannies (up in fluorescent light fixtures, under dressers, behind books on shelves, in the labyrinth of all of the cans in pantry, in a pair shoes) and were being roused from their winter torpor, I think, by the warmer temperatures and growing day lengths.
What we are seeing is probably the tip of the hibernating horde of stink bugs! A few will come out to check out the weather conditions and then either wander off to die (or get caught in one of my stink bug bottles) or tuck themselves back into one of their hidden hibernaculae.
The ability of these stink bugs to overwinter is remarkable. There is some mortality among the hibernating bugs, but a significant percentage of even the outside hibernators make it through to spring and to their opportunity to mate. Colder temperatures, though, reduce this percentage of survival. Several models of climate change and global warming have included increased survival of stink bugs at higher and higher latitudes with, then, significantly larger spring and summer populations of this potentially destructive pest. When you factor in their ability to find their way into our houses and spend the winter months hibernating in tiny crevices and hideouts all around us the survival rate goes up to near 100% and the northern, “freeze” boundary disappears altogether.
My third sign of spring came from a colleague at Penn State. I got an email from Rob Bridges a few weeks ago in which he described watching some crows feeding on a road killed rabbit out in from of his house (Rob and I have many interesting conversations like this!). As he watched, though, the crows were suddenly sent flying by the arrival of a turkey vulture who then proceed to dine on the pressed rabbit.
This surprised me because turkey vultures that live around here in the summer are expected to spend their winters in Florida or Texas. Our cold winter temperatures would not only put a great deal of stress on the vultures but also prevent the generation of the thermal updrafts that they require to sustain their long, daily flights in which they search for food. Turkey vultures also primarily use their sense of smell to find carcasses on which to feed. Cold temperatures will inhibit both the generation and the distribution of these scent lines!
Turkey vultures are also quite gregarious. They night roost in large, communal groups and usually forage or day roost in smaller groups (called “wakes”). A turkey vulture is seldom seen without companions! Where are the other members of his wake hiding out?
Hinckley, Ohio (a small town just south of Cleveland) celebrates the spring return of their turkey vultures with a “Return of the Buzzard” day on March 15. For the past fifty-seven years they have been greeting the returning flocks of turkey vultures as an important sign of spring. It makes more sense than Groundhog Day, that’s for sure (although it less aesthetically pleasing than Housecat Day!). But, Lower Burrell, PA has an eight week jump on Hinckley! The vultures are back!
Finally, a very unwanted Sign of Spring came in on our dog, Izzy: black legged ticks!
I have removed three ticks over the past few days from Izzy. They were adult, female “black legged ticks” (also called “deer ticks,” but most properly called Ixodes scapularis). These adult forms had been very abundant back in the Fall and some, apparently, have successfully overwintered and are still seeking the blood meal they need to make their eggs.
Pennsylvania is experiencing an ongoing population explosion of black-legged ticks. The reason for this increase is not precisely known. Possibly the increased populations of rodents (especially white-footed mice) particularly in our suburban ecosystems may be providing the ticks with an abundance of small hosts on which to feed. Black-legged ticks, then, in their larval and nymphal life stages are very likely to find a white-footed mouse from which they can take a blood meal. These mice are also significant reservoirs for the bacterium that causes Lyme disease, so the ticks that feed on them have a very high probability of assimilating and then passing on these bacteria.
The true “spring” blacklegged ticks are the eight-legged nymphs that have been overwintering since last summer. These are the “medium sized” deer ticks and very significantly they may be carrying the bacterium that causes Lyme disease. These ticks will feed on a wide range of mammals (from white-footed mice to dogs to cats to deer to humans). Both dogs and humans are susceptible to Lyme and both are experiencing out of control epidemics of the disease!
So, bees, stink bugs, vultures and ticks! Quite a quartet of Spring! I hope to see some crocuses, red maple flowers and flocks of robins and bluebirds soon, too!