RAPTORS SUCCEEDING RAPTORS

     In winter, during the 1970's and 1980's, I would see up to a half dozen, or more, rough-legged hawks in an hour's drive by large, open fields harvested to the ground around New Holland, Lancaster County, Pennsylvania.  Though they appear big, rough-legs mostly prey on field mice.  

     Rough-legs nest on cliffs in the Arctic tundra, but some came as far south as Pennsylvania to spend  winters searching for mice in extensive, relatively snow-free fields that resemble the treeless tundra.  But during the winters of the 1990's, and through the Twenty-first Century, so far, I noticed a dwindling of rough-legs to almost none all winter in Lancaster County fields that once harbored them.

     I think there are three theories why rough-legged hawks are almost nonexistent, locally, in recent years.  One could be a lack of sufficient mice to feed them all through a winter because of intensive, constant cultivation and harvesting to the ground that doesn't allow enough food and cover for mouse populations.  Or, because of global warming, rough-legs don't need to migrate this far south to find abundant rodents.  

     A third theory could be an increase in red-tailed hawk populations in Lancaster County croplands during the 1990's.  Red-tails are big hawks, strong and aggressive.  Perhaps red-tails chased out rough-legs to claim the farmland for themselves to hunt in and raise young.

     Red-tails had been common in that open cropland around New Holland for several years.  They annually raised young in lone trees in local fields, and many of them stayed through winter to hunt rodents and other creatures.  But their population dropped during the Twenty-first Century.

     Due to a lessened use of DDT, laws protecting hawks, eagles and owls, and their own adapting to human-made habitats, numbers of the huge, powerful bald eagles increased dramatically across North America, including here in Lancaster County croplands.  My theory is the eagles here easily pushed out red-tails and used the hawks' stick cradles in lone trees as their own to raise eaglets.  And the eagles used the hunting and scavenging sources the red-tails had.  

     All this is theory on my part, based on my observations as a New Holland resident through several years.  Succession like this is constantly happening everywhere throughout the globe.  Nature is never static, but always changing.           

Comments

Post a Comment

Popular posts from this blog

SPRING ON THE UPPER CHESAPEAKE

      I visited the Upper Chesapeake Bay at the Community Park of Northeast, Maryland one afternoon about the middle of March a few years ago, as I had several times in different seasons before that day.  This time, I went there to spot migrating water birds of various kinds.        Because of their high numbers, gulls and ducks were the dominant birds on the ice, and strips of open water among the slabs of ice because of the warming weather in March.  Most of the handsome ring-billed, herring and great black-backed gulls stood picturesquely on slabs of ice.        The attractive, adult ring-billed and herring gulls are mostly gray on top, white below, and look much alike, except the herrings are larger and have a red mark on their beaks, whereas each ring-bill has a black "ring" around its bill.  Largest of these gulls, the stately, mature black-backs have black backs and upper wings and are white below, making a striking, attractive plumage pattern.        All three of thos
Read more

DADDY-LONG-LEGS

     During summer, over the years in southeastern Pennsylvania, I've seen many daddy-long-legs on the bark of tree trunks on lawns, and in parks and woods.  They blend into the color of tree bark well and are difficult to see.  Many people never see them at all until those camouflaged little critters are pointed out by people in the know about them.        Daddy-long-legs have eight, really long, thin legs, but they are not spiders.  But they are arachnids, and related to spiders.  These attractive, little creatures, called daddy-long-legs because of their long legs, have quarter-inch, compact bodies raised on stilt-like legs.  They have two dark eyes and feel the vibrations of birds and other predators with their legs.  But these arachnids have no venom, or silk to make webs.        Daddy-long-legs, like all other living beings, are part of several food chains.  They consume tiny invertebrates and decaying plant and animal materials they find on tree bark.  And, in turn, many of
Read more

FATHER FINCHES FEEDING FLEDGINGS

     While sitting on our back deck to enjoy the lovely scenery and weather during the afternoon of July 21, 2023, I noticed a tiny, red speck in our tall Norway spruce tree on our suburban lawn in southeastern Pennsylvania.  Peering at that red spot with 16 power binoculars, I saw it was a beautiful male house finch feeding three fledgling house finches; his offspring.  Those gray and dark-streaked young birds fluttered their wings vigorously while being fed invertebrates and seeds.  And the wild charm of those birds was decidedly enhanced by the deep-green of the needled spruce boughs.        Those four house finches were a lovely, exciting sight to me.  I know that species of small birds raises young in our neighborhood every summer, including a pair of house finches that hatch offspring on a support under an awning over our deck.  But never before had I watched a father house finch feed his young outside their twig and grass cradle.  And when that male finch flew off the spruce lim
Read more