I have been watching the riotous weather patterns of the past few weeks with great interest. The powerful fronts crossing over us that send temperatures skyrocketing and then plummeting and trigger the violent storms and high winds that equally shake our houses and forests always seem to surprise us even though they occur each year with clock-like regularity. This is a very poor place for plants and animals to rely on temperature as an index of seasonal time!
Migrating birds arrive on the first warm days of late winter or early spring. We first saw robins in our yard on February 15, and red-winged blackbirds down along the stream sides on March 2. Blue birds were first seen streaking across the field on March 19, and grackles first showed up under the birdfeeders on March 25. Towhees arrived on April 8. Juncos began to thin out (as they headed north, I assumed) in the warmer days of early March, but then were back in numbers even greater than their winter densities in the colder days of early April. My guess is that they started up to their more northern breeding territories but then came back for shelter and sunflower seed sustenance when winter showed signs of returning.
To be the first to arrive at your summer breeding territories is a great benefit to a bird. But, the danger of freezing to death in a sudden storm, or being unable to find a reliable supply of food because of an early spring snow makes the early arrival a real-life adventure. We watched some very confused looking robins hopping about on a fresh snow pack trying to scare up some earthworms that had been so abundant just the day before!
On April 7 I saw my first butterfly (a fritillary) and the next day Deborah saw a mourning cloak down on the Roaring Run hiking trail. Last year at this time we had also seen spring azure butterflies up on a nearby wooded ridge. These species overwinter as adults and come out of their cold weather torpor to dash out on the first truly warm and sunny days. To be the first to find nectar, the first to find a mate, the first to lay eggs and start the set of reproductive cycles of the season are of great benefit to the individuals. Their genes will multiply more rapidly. Their influence on the future will be amplified. But there is also the very real possibility that they will get caught away from their protected hibernaculae and freeze because they mistimed the onset of night or the arrival of a storm front.
On April 15 we sat on our deck and watched solitary bumble bees fly like little blimps on their straight-line tracks. They too are walking a fine line of risk and benefit. Early bees do get the nectar and are able to jump start their reproductive cycles, but there are numerous descriptions in the literature of bumble bees dropping out of flight as the air temperature around them dips below a critical minimum level. The fallen bees then freeze overnight and thus lose their chance to participate in structuring the next generation.
In all of these species there is a continuous ebb and flow of daring and caution, a continuous re-structuring of adventurous and conservative behaviors which are each rewarded or punished depending on the particulars of the weather patterns of any given year. Some days the early bird WILL get the worm, while on other days the early bird, unfortunately, will not end up so well.