The last of April and early May were remarkable for the cold, wet weather here in Maryland and throughout the Mid-Atlantic. I heard we had 14 straight days of measurable rain and the thermometer was clearly forgetting that the spring equinox was six weeks ago. As we pulled into our rural road, returning from a hot supper out, there was a good-sized flock of Purple Martins, maybe 25 or 30, blocking our way. As I slowed down surprisingly only a few flew away and even those birds quickly landed a short distance further down the road as if to claim it for themselves. I ran an obstacle course through them trying hard to straddle as many as possible. What was going on? These were not the usual energetic, swooping, and vocal swallows one usually sees each spring. The next morning the martins were still on the road, but now there were several squashed bodies of those that had refused to yield to traffic. This went on for several days and the body count mounted until the survivors finally disappeared.
About this same time I was at a party where friends of mine recounted another episode of strange martin behavior occurring about the same time in the cold and drizzle. This couple are bird lovers and astute observers of the flora and fauna in their yard. They noticed a martin with unusually droopy wings perched on the porch of their Purple Martin house. He flew away when they investigated with a ladder but one of the apartments was jammed with five other stuporous martins. The entry to another apartment was blocked by a dead bird, and when he was removed another five birds flew out the now open door. What’s going on?
As you probably know Purple Martins are long distance migrants. The older scouts first arrive in the Chesapeake region in the second half of March, seeking their prior year’s nesting site. The younger birds make the long trip from South America up to four weeks later. The martins are the largest New World swallows and the only swallows displaying sexual dimorphism–the sexes look different. The eastern subspecies has the unusual trait of almost entirely depending upon man-made cavities for nesting. Hundreds, perhaps thousands of years ago Native Americans in the east started hanging hollowed-out gourds to attract the sociable martins. European settlers noticed this and expanded the practice which we continue today. After thousands of generations of birds using these man-made nesting sites the eastern martins have essentially abandoned the use of natural cavities.
The concept of long distant and massive bird migrations has not always been known. This makes sense since until the end of the 15th century we weren’t even aware of the distant continents themselves. There was a general idea that the disappearing fall birds were hibernating somewhere, just like the frogs, turtles, and some mammals. I’ve read old accounts of torpid spring martins that were assumed to be waking up from their winter’s sleep and wonder if they were describing the same behavior of our martins last month.
So here’s my theory of what’s going on with the martins. They are tough birds but after a two thousand mile migration their body weight is significantly reduced and the birds are vulnerable. The ill-timed cold snap and rains greeted them in their already weakened state making it difficult to fly, or even avoid an oncoming car. Martins usually forage during flight, but if they are too weak to fly hunger will compound their plight. Possibly the flying insects they feed on were also in short supply due to the inclement weather. I’ll bet they were huddled in the apartment and on the dark road in a last desperate search for warmth. In the open they were clearly easy prey for predator hawks as well as the squashing cars.
Let me know if you’ve noticed similar behavior or if you have any additional thoughts. It may well be a tough breeding year or two for the martins, at least in our neck of the woods.