Some Raptor Counterparts

     Raptors are hawks, eagles and owls; all birds of prey.  Though hawks and eagles are in one family and owls are in another, all species of both families have long, curved talons for killing prey and sharp, curved beaks for tearing chunks of meat off the animals they kill.  Each family developed the same bodily equipment to do a similar job in life, the hawks during the day and the owls at night.  Those similar features in different families of life is called convergence, a coming together. 
     Hawks hunting victims during the day and owls doing so mostly at night reduces direct competition for food, which allows both predatory families to live in the same habitats.  Actually, species of each family have more competition from members of their own family than from other kinds of life.  That is why each species of a family lives in its own niche away from the niches of its relatives; to reduce rivalry for space and food.
     Being hunters, all hawks and owls blend into their surroundings to better their chances of catching food.  Hawks are camouflaged to better ambush prey that doesn't see them.  And owls are camouflaged so they can better hide by day on a roost, without being spotted by jays, crows and other types of birds that would harass them if they saw them.  When not heckled by birds, the owls can get better rest and be refreshed to hunt the next night.
     There are at least five examples of raptor counterparts in southeastern Pennsylvania, as elsewhere throughout the world.  Interestingly, each set of counterparts are about the same size.  Red-tailed hawks and great horned owls are counterparts living permanently in upland woods and older suburban areas with their many tall trees.  These raptors hunt in the woods, suburbs and neighboring fields for a variety of rodents and other animals, the red-tails by day and the owls mostly at night.  Red-tails specialize in catching gray squirrels, which is a daytime rodent while the owls snare a lot of mice and rats at night.  Both these raptors hatch young in open, stick nurseries in tree tops.
     Permanent residents as species, the little American kestrels and screech owls mostly hunt small rodents and larger insects at different times of day in fields and woodland edges.  Both these raptors compete for tree cavities and nest boxes erected for them in woods, suburbs and lone trees in fields to raise young in.  And these species spend winter nights in those hollows as well.
     Red-shouldered hawks and barred owls live and raise offspring in bottomland woods and older suburbs near larger bodies of water.  Red-shoulders rear babies in stick nests while the owls do so in tree cavities.  Both species consume mice, small birds, frogs, larger insects and other critters they catch in wooded bottomlands and suburbs.  And the hooting of barred owls and horned owls is frightening to some people who hear it in the middle of the night.  Each of these large owl species have a different rythm of hooting that identifies it.
     Northern harriers and short-eared owls are adapted to open habitats with tall grass and crops, where they catch mice and small birds.  These two species are almost completely winter residents in southeastern Pennsylvania.  And because of their similar habitat, they hunt the same way.  Instead of perching on trees and watching for victims as many of their relatives do, harriers and short-ears actively cruise back and forth low over the fields as they watch and listen for prey animals.  When a victim is spotted, each raptor suddenly drops to snare it in its claws.
     Sometimes harriers and short-ears hunt at the same time because short-ears start to hunt late in a winter afternoon before the harriers have retired into the long grass for the night.  It's exciting to see these two counterparts cruising the same fields at the same time.
      Rough-legged hawks and snowy owls both raise young on the Arctic tundra, where they mostly catch lemmings and voles, both of which are rodents.  Rough-legs come south to cropland and other open country in the United States every winter to avoid starving on the tundra.  Here they mostly eat mice.  But the big, elegant snowies, mostly the young of the year,  come south to open country, including farmland, one winter in about every four.  They will stay on the tundra all winter if there are enough rodents to eat there.  But if not, south they come, sometimes in impressive numbers that is sure to make the news.  Here in the Lower 48, snowy owls catch and eat critters from mice to snow geese.              
     Hawks and owls are counterparts of each other, in every habitat, so they can hunt the same animals without direct competition with each other.  Without rivalry for space and food, both these groups of birds can survive in the same habitats, which increases their chances of species survival.