While driving along expressways in the eastern United States, I noticed several times that little flocks of rock pigeons were perched on wires, like musical notes on sheets of music, above bridges along those highways. Those pigeons live and raise young on support beams under those bridges where they are safe from the elements and most predators. Only crows might be able to eat the eggs or small young of the pigeons under those protecting bridges.
Rock pigeons are originally from the Mediterranian Sea area where they traditionally roost and nest on the rocky cliffs, safe from most predators, except peregrine falcons and other kinds of raptors. Pigeons' feathers are mostly sooty-gray, which blends them into the color of those rocky cliffs and conceals them from predator eyes. But they also have lighter gray on their wings, a purple and green sheen on their necks and red legs.
These beautiful birds were long ago domesticated for meat, eggs and sport by Europeans and were taken everywhere on Earth by those peoples. Many pigeons became feral and now live wild in cities and farmland throughout much of the world, including here in North America.
Pigeons live year around in cities, and rear two offspring per brood on ledges of tall buildings during warmer months. There they are safe from predators, except crows and certain raptors, particularly peregrine falcons. City pigeons ingest weed seeds from vacant lots, grain from bird feeders and a variety of edibles, including peanuts and popcorn, fed to them by kindly people.
In farmland, pigeons perch during the day on top of certain silos, which are the tallest structures on a farm, but live permanently in some barns and raise young there during warmer months. Incidentally, each pair of rock pigeons, whatever habitat they live in, stay together for life, and produce two young a month, during warmer months in temperate climates. And in farmland, pigeons feast on weed seeds, and grain missed by automatic harvesters in grain fields, including wheat and corn fields. Pigeons in North America, as almost everywhere else on Earth, are totally dependent on human activities to survive.
Noticing rock pigeons perched in scattered rows on wires over bridges along expressways is a new, and interesting, revelation for me. Those adaptable birds found another habitat to live and nest in, which helps increase their numbers.
Rock pigeons, like all species of pigeons and doves, worldwide, raise two staggered broods of young at once during warmer months. When the first brood of offspring of a year is half-grown, the female of each pair lays two eggs in another cradle. Both the male and female of each pair take turns brooding the second clutch of eggs and feeding the first brood until they fledge their nursery. The second brood hatches about when the first brood leaves its nursery. When the second brood is half-grown, the female of each pair lays two eggs in the first nursery. The pair shares feeding and brooding responsibilities. In this way, each pair of pigeons and doves raises an average of two young per month, IF their flimsy nests aren't blown off their supports, and if the young aren't eaten by crows, jays, raccoons, black rat snakes and other kinds of predators.
Rock pigeons, and all pigeon and dove species, feed their young "pigeon's milk" which is a regurgitated mixture of pre-digested seeds and throat phlegm pumped into each youngster's throat.
Pigeons have come a long way from their Mediterranean Sea cliffs. Their adapting to human-made structures and farming activities has increased their numbers greatly, making them a successful species. And their nesting under expressway bridges with all that unending traffic noise is a real adjustment for survival. Life, in general, finds ways to survive.
Tuesday, July 30, 2019
Thursday, July 18, 2019
Farmland Swallows and Sparrows
Several kinds of birds feed in southeastern Pennsylvania farmland in summer, including American robins, common grackles, killdeer plovers, mourning doves, Canada geese and others. And two other cropland bird species- barn swallows and house sparrows, are small, adaptable, raise young in barns and get much of their food in nearby fields.
However, those swallows and sparrows don't compete for food or shelter with each other, which is why they flourish in the same habitats. And each kind rears two broods of young every summer, which increases their populations to the point of being abundant and omnipresent in summer farmland in this area.
But barn swallows and house sparrows have characteristics that differ from each other. And each species is built for what it does to get food. It's entertaining to watch little flocks of the slender, streamlined swallows sweep swiftly over fields and meadows, swirling and diving after flying insects, without collision with their fellow swallows! By mid-July, through August, many adult swallows and their young of the year scour the fields of flying insects, and line up on roadside wires to rest between feeding forays.
Barn swallows are metallic purple on top and light orange below. They have narrow, swept-back wings for fast flight and forked tails for mid-air maneuvers at top speed.
Native to North America, barn swallows originally nested in the mouths of caves and on rock cliffs. Today these adaptable birds hatch chicks on the sides of support beams in barns and under small bridges, all in farmland where insects are abundant. They build their protecting nurseries of mud pellets from mud they gather along streams and ponds and plaster those pellets, one by one, to the beams. Due to that adaptation, there probably are more barn swallows in North America today than ever in their history.
During August and September, barn swallows gather in swarms and drift south to Central America and northern South America where flying insects are abundant during northern winters. But their mud pellet nests still cling to beams as reminders of their having been in this area.
House sparrows are not sparrows, but weaver finches from Eurasia where they long ago adapted to agricultural practices and living in barns and village buildings. Today in the Old World, and in the Americas, house sparrows raise young in sheltering crevices in barns and other buildings, including in cities, and feed on weed and grass seeds, "waste" grain in fields and invertebrates, all on the ground in cropland near where they hatched. House sparrows are permanent residents and don't migrate; living all their lives in one area. However, because of population pressures, these birds spread across the landscape, generation after generation, as some young birds seek homes near where they hatched.
House sparrows are brown with darker streaks, which camouflage them in fields and around nesting sites. Males in summer are handsome with black "bibs", gray crowns and cheeks, and chestnut necks. Though males don't sing to attract a mate, they do chirp and strut vigorously to gain a female's attention and affection.
By mid-summer, flocks of 50 or more house sparrows, young and older, gather here and there in grain fields and along country roads to feed on invertebrates, grain missed by harvesters and weed and grass seeds. When those flocks are on rural roads to eat spilled grain, they all fly up at once into nearby shrubbery or corn fields to perch and wait for vehicular traffic to pass by. Then they flutter down to the road again to continue ingesting the grain off the blacktop until the next vehicle approaches.
When riding in farmland in summer, watch for barn swallows, house sparrows and other kinds of adaptable birds along the road and in bordering fields. They add more pleasure to the ride.
However, those swallows and sparrows don't compete for food or shelter with each other, which is why they flourish in the same habitats. And each kind rears two broods of young every summer, which increases their populations to the point of being abundant and omnipresent in summer farmland in this area.
But barn swallows and house sparrows have characteristics that differ from each other. And each species is built for what it does to get food. It's entertaining to watch little flocks of the slender, streamlined swallows sweep swiftly over fields and meadows, swirling and diving after flying insects, without collision with their fellow swallows! By mid-July, through August, many adult swallows and their young of the year scour the fields of flying insects, and line up on roadside wires to rest between feeding forays.
Barn swallows are metallic purple on top and light orange below. They have narrow, swept-back wings for fast flight and forked tails for mid-air maneuvers at top speed.
Native to North America, barn swallows originally nested in the mouths of caves and on rock cliffs. Today these adaptable birds hatch chicks on the sides of support beams in barns and under small bridges, all in farmland where insects are abundant. They build their protecting nurseries of mud pellets from mud they gather along streams and ponds and plaster those pellets, one by one, to the beams. Due to that adaptation, there probably are more barn swallows in North America today than ever in their history.
During August and September, barn swallows gather in swarms and drift south to Central America and northern South America where flying insects are abundant during northern winters. But their mud pellet nests still cling to beams as reminders of their having been in this area.
House sparrows are not sparrows, but weaver finches from Eurasia where they long ago adapted to agricultural practices and living in barns and village buildings. Today in the Old World, and in the Americas, house sparrows raise young in sheltering crevices in barns and other buildings, including in cities, and feed on weed and grass seeds, "waste" grain in fields and invertebrates, all on the ground in cropland near where they hatched. House sparrows are permanent residents and don't migrate; living all their lives in one area. However, because of population pressures, these birds spread across the landscape, generation after generation, as some young birds seek homes near where they hatched.
House sparrows are brown with darker streaks, which camouflage them in fields and around nesting sites. Males in summer are handsome with black "bibs", gray crowns and cheeks, and chestnut necks. Though males don't sing to attract a mate, they do chirp and strut vigorously to gain a female's attention and affection.
By mid-summer, flocks of 50 or more house sparrows, young and older, gather here and there in grain fields and along country roads to feed on invertebrates, grain missed by harvesters and weed and grass seeds. When those flocks are on rural roads to eat spilled grain, they all fly up at once into nearby shrubbery or corn fields to perch and wait for vehicular traffic to pass by. Then they flutter down to the road again to continue ingesting the grain off the blacktop until the next vehicle approaches.
When riding in farmland in summer, watch for barn swallows, house sparrows and other kinds of adaptable birds along the road and in bordering fields. They add more pleasure to the ride.
Saturday, July 13, 2019
White Clover and Fireflies
Short-grass lawns are widespread and abundant human-made habitats in much of the United States. Those regularly cut lawns of only a couple inches tall provide little food and cover to wildlife and seem barren. But, besides the planted grass, two forms of life are overwhelmingly and obviously abundant on many mowed lawns- white clover and fireflies. Together, they add much beauty and entertainment to those lawns, particularly in July.
Originally from Eurasia, the great abundance of white blossoms on white clover plants turn many lawns silver, because of regular lawn mowing. Cutting clover flowers off encourages the plants to grow new blooms, week after week, all summer, and into autumn.
Fireflies inhabit most every habitat in the eastern United States. As larvae, these abundant native beetles inhabit soil at the plant roots level in woods, fields and lawns, where they prey on tiny snails, slugs and other invertebrates in the ground.
And most every dusk from the third week of June until the end of July, with a peak of abundance early in July, hordes of adult, winged male fireflies crawl up grass stems and white clover plants and launch themselves into the air to find females to mate with. They hover like thousands of tiny helicopters and flash their cold, abdominal lights to females still in the grass and clover, then fly a little higher and flash again and again. Multitudes of blinking male fireflies create a magical, fantasy-land in the dark of July nights in woods, fields and lawns.
Lawns sprinkled liberally with white clover flowers are also lively with honey bees, bumble bees and other kinds of insects that buzz from blossom to blossom to sip the sugary nectar of those blooms. Regular mowing encourages clover plants to produce new flowers every week, which provides insects with a continuous source of nectar all summer and into autumn.
Many people benefit from fireflies and white clover on short-grass lawns. The fireflies provide hours of intriguing beauty and white clover blooms give us beauty, and honey, through the work of female worker honey bees. The bees sip nectar from clover blossoms and swallow it into a special stomach that changes it to honey as they fly back to their home in a tree hollow or hive. Each bee regurgitates that honey into a waxy cell where it is stored to feed the queen bee, larvae and drones, and as food for overwintering worker females. Bee keepers, however, extract and sell some of that stored honey, including white clover honey, and/or consume it themselves.
The six-sided, wax cells to store honey and raise larvae, by the way, are made from honey worker bees ate and "sweated" through their bodies. They scrape the wax off themselves to shape the cells. And scientists discovered that six sides are the strongest shape, and most efficient use of space in nature.
Nature is resilient. Even short-grass lawns are not barren of life. White clover and fireflies live in that human-made habitat in overwhelming abundance. And other kinds of small plants and animals reside there as well. Some lawns are two-inch-tall "jungles" of life.
Lawns cover many thousands of acres in the United States. They, and other human-made habitats, might appear barren at first, but they are not lifeless. To me, life in built environments that serve people are inspiring because those living beings' adaptations, including multitudes of white clovers and fireflies, allow them to thrive in human-disturbed places, which increases that lifes' populations. Built habitats are interesting to me because of the adaptable life in them; life that has a future because it can adjust to less than ideal conditions.
Originally from Eurasia, the great abundance of white blossoms on white clover plants turn many lawns silver, because of regular lawn mowing. Cutting clover flowers off encourages the plants to grow new blooms, week after week, all summer, and into autumn.
Fireflies inhabit most every habitat in the eastern United States. As larvae, these abundant native beetles inhabit soil at the plant roots level in woods, fields and lawns, where they prey on tiny snails, slugs and other invertebrates in the ground.
And most every dusk from the third week of June until the end of July, with a peak of abundance early in July, hordes of adult, winged male fireflies crawl up grass stems and white clover plants and launch themselves into the air to find females to mate with. They hover like thousands of tiny helicopters and flash their cold, abdominal lights to females still in the grass and clover, then fly a little higher and flash again and again. Multitudes of blinking male fireflies create a magical, fantasy-land in the dark of July nights in woods, fields and lawns.
Lawns sprinkled liberally with white clover flowers are also lively with honey bees, bumble bees and other kinds of insects that buzz from blossom to blossom to sip the sugary nectar of those blooms. Regular mowing encourages clover plants to produce new flowers every week, which provides insects with a continuous source of nectar all summer and into autumn.
Many people benefit from fireflies and white clover on short-grass lawns. The fireflies provide hours of intriguing beauty and white clover blooms give us beauty, and honey, through the work of female worker honey bees. The bees sip nectar from clover blossoms and swallow it into a special stomach that changes it to honey as they fly back to their home in a tree hollow or hive. Each bee regurgitates that honey into a waxy cell where it is stored to feed the queen bee, larvae and drones, and as food for overwintering worker females. Bee keepers, however, extract and sell some of that stored honey, including white clover honey, and/or consume it themselves.
The six-sided, wax cells to store honey and raise larvae, by the way, are made from honey worker bees ate and "sweated" through their bodies. They scrape the wax off themselves to shape the cells. And scientists discovered that six sides are the strongest shape, and most efficient use of space in nature.
Nature is resilient. Even short-grass lawns are not barren of life. White clover and fireflies live in that human-made habitat in overwhelming abundance. And other kinds of small plants and animals reside there as well. Some lawns are two-inch-tall "jungles" of life.
Lawns cover many thousands of acres in the United States. They, and other human-made habitats, might appear barren at first, but they are not lifeless. To me, life in built environments that serve people are inspiring because those living beings' adaptations, including multitudes of white clovers and fireflies, allow them to thrive in human-disturbed places, which increases that lifes' populations. Built habitats are interesting to me because of the adaptable life in them; life that has a future because it can adjust to less than ideal conditions.
Sunday, July 7, 2019
Two Beautiful Damselflies
For about an hour one recent, hot afternoon in the farmland of eastern Lancaster County, Pennsylvania, I was driving around a bit to see what was new in nature. I didn't see much wildlife until I came to a clear, cold brook running through a grove of planted willow trees, and closely paralleling a rural road. Because that stretch of road was shaded and relatively cool, I stopped to see what wildlife was in that brook, and the ground, trees and jewelweeds around it.
Immediately, I saw more male black-winged damselflies in that 50-yard stretch of waterway than I have ever seen in other brooks of that size. Some metallic-green, male damselflies with four black wings were fluttering together daintily, like pretty butterflies in sunbeams, above the shallow waterway, creating a beautiful, entertaining sight. Their "dancing" was their attempts at intimidating each other away from a prime breeding site, and to attract females to the winners for mating. I was taken with their bold iridescence in slanting shafts of sunlight that penetrated the shadows.
Southeastern Pennsylvania has two common kinds of damselflies, that are striking in appearance, but overlooked by most people- black-winged and bluet. Black-wings of the broad-winged damselfly family and bluets of the narrow-winged damselflies are as lovely around clear, running water as any bird or flower is on land.
Male black-wings have iridescent-green, or blue, bodies and four black wings they hold upright over their bodies when at rest. Their females are brownish all over, which allows them to blend into their surroundings. Male bluets are blue with black rings on their abdomens and four clear wings that are held above their bodies. Their mates are similar, but paler.
Related to dragonflies, these two families of damselflies, and dragonflies, have characteristics in common. Dragonflies and damselflies start life as wingless nymphs, larvae, in water. All those nymphs eat tiny, aquatic invertebrates they find in mud or under stones.
Nymphs of both families of damselflies have feathery-looking gills poking from the ends of their abdomens. And they are all the color of mud and stones, which blends them into their niches, the black-wing larvae among stones in small waterways and the bluet young in the mud of ponds.
Adults of both families of damselflies have narrow abdomens, to the point that they are almost hard to see. Adults of both groups consume aphids and other kinds of small, soft-bodied insects on plants and in the air. And damselflies are part of food chains because preying mantises, spiders and several kinds of birds eat them.
But the two-inch-long black-winged damselflies and the one-inch-long bluet damselflies also have differences. Black-winged females spawn eggs in the tissues of plants in the slow shallows of brooks and streams in tree-shaded habitats. Bluet females, however, place their eggs on mats of alga, or other vegetation, in sun-warmed, still ponds. These damselfly species reduce competition for living space and food with each other by being adapted to different niches. And being adapted to different niches created each kind of damselfly.
Interestingly, male black-winged damselflies repeatedly open their black wings slowly, then snap them shut when they are perched on brookside vegetation. This probably is a communication to female black-wings that they are present and available for mating.
The attractive bluet damselflies are also entertaining to watch, but in different ways than the black-wings. Bluets often form groups on floating mats of alga and other aquatic plants where they mate and lay eggs on the wet vegetation. They also dart about, often in pairs, over the water when chasing each other or potential prey. But bluets are so thin they are often difficult to see over or on the sky-reflecting waters' surfaces. One has to look closely to spot them.
Look for these two kinds of damselflies in appropriate habitats. Though unknown insects, they are big in beauty and intrigue.
Immediately, I saw more male black-winged damselflies in that 50-yard stretch of waterway than I have ever seen in other brooks of that size. Some metallic-green, male damselflies with four black wings were fluttering together daintily, like pretty butterflies in sunbeams, above the shallow waterway, creating a beautiful, entertaining sight. Their "dancing" was their attempts at intimidating each other away from a prime breeding site, and to attract females to the winners for mating. I was taken with their bold iridescence in slanting shafts of sunlight that penetrated the shadows.
Southeastern Pennsylvania has two common kinds of damselflies, that are striking in appearance, but overlooked by most people- black-winged and bluet. Black-wings of the broad-winged damselfly family and bluets of the narrow-winged damselflies are as lovely around clear, running water as any bird or flower is on land.
Male black-wings have iridescent-green, or blue, bodies and four black wings they hold upright over their bodies when at rest. Their females are brownish all over, which allows them to blend into their surroundings. Male bluets are blue with black rings on their abdomens and four clear wings that are held above their bodies. Their mates are similar, but paler.
Related to dragonflies, these two families of damselflies, and dragonflies, have characteristics in common. Dragonflies and damselflies start life as wingless nymphs, larvae, in water. All those nymphs eat tiny, aquatic invertebrates they find in mud or under stones.
Nymphs of both families of damselflies have feathery-looking gills poking from the ends of their abdomens. And they are all the color of mud and stones, which blends them into their niches, the black-wing larvae among stones in small waterways and the bluet young in the mud of ponds.
Adults of both families of damselflies have narrow abdomens, to the point that they are almost hard to see. Adults of both groups consume aphids and other kinds of small, soft-bodied insects on plants and in the air. And damselflies are part of food chains because preying mantises, spiders and several kinds of birds eat them.
But the two-inch-long black-winged damselflies and the one-inch-long bluet damselflies also have differences. Black-winged females spawn eggs in the tissues of plants in the slow shallows of brooks and streams in tree-shaded habitats. Bluet females, however, place their eggs on mats of alga, or other vegetation, in sun-warmed, still ponds. These damselfly species reduce competition for living space and food with each other by being adapted to different niches. And being adapted to different niches created each kind of damselfly.
Interestingly, male black-winged damselflies repeatedly open their black wings slowly, then snap them shut when they are perched on brookside vegetation. This probably is a communication to female black-wings that they are present and available for mating.
The attractive bluet damselflies are also entertaining to watch, but in different ways than the black-wings. Bluets often form groups on floating mats of alga and other aquatic plants where they mate and lay eggs on the wet vegetation. They also dart about, often in pairs, over the water when chasing each other or potential prey. But bluets are so thin they are often difficult to see over or on the sky-reflecting waters' surfaces. One has to look closely to spot them.
Look for these two kinds of damselflies in appropriate habitats. Though unknown insects, they are big in beauty and intrigue.
Tuesday, July 2, 2019
Evolving Chats and Thrashers
Several kinds of birds nest in dense thickets in hedgerows and woodland edges in southeastern Pennsylvania, as elsewhere in the eastern half of the United States. Those species include northern cardinals, blue grosbeaks, gray catbirds, brown thrashers, white-eyed vireos, yellow-breasted chats and others. Those thickets offer excellent shelter, and food in the forms of invertebrates and berries. And of all the bird species that raise young in those jungles of shrubbery and vines, chats and thrashers have the more intriguing life histories.
Chats are far more often heard than seen because of the males' unique vocalizations and bizarre actions to establish nesting territories and attract mates for rearing offspring. Male chats utter whistles, clucks, toots and other strange notes, as well as pleasant songs. And male chats repeatedly rise from thickets in floppy, attention-getting flight, while singing, then drop back into the shrubbery.
With the genders being similar, chats are pretty birds, being olive-brown on top and bright-yellow below. They winter in Central America.
The chats' ancestry is the most interesting thing about them. They seem to be made of traits and parts leftover from other families of birds. They have been considered to be a New World wood warbler, but they are not a warbler. Currently, they are classified as a member of the blackbird/oriole family. Chats, however, are in a genus of their own because they are so unique. And over millenia, they may diverge into other species.
In many of their habits, chats resemble the mimidae family of birds, which includes mockingbirds, catbirds and thrashers. Chats skulk in the shadowed jungles of shrubs and vines like minidae. And they sing similarly to northern mockingbirds, including at night, and imitating other birds' sounds.
Chats often display the postures of North American cuckoos, kind of bent over with long tails drooping. But, apparently, chats are not members of the mimidae or the cuckoo families. Perhaps chats resemble those families because they share habitats- convergent evolution that shapes critters from different families into similar beings to cope with their environment in common.
Over future millenia, brown thrashers could be roadrunner-like, a species related to North American cuckoos. Those thrashers are built like roadrunners, but smaller, and have strong legs for running after prey, as roadrunners do.
I have seen brown thrashers, on foot, chasing after insect prey under thickets and across short-grass lawns. They always remind me of small, brown roadrunners.
Three closely related kinds of thrashers that live in deserts in southwestern North America, Leconte's, California and Crissal thrashers, are already roadrunner-like. Roadrunners, too, live in deserts where they run down lizards, snakes, mice and invertebrates. Those three kinds of thrashers seldom fly, but run fast enough, with their tails erect, to catch invertebrates and small snakes and lizards. These desert thrashers, through millenia, developed stronger, faster legs because the swiftest ones caught prey and survived, as roadrunners must have done. Maybe, some day, brown thrashers of the east will be more roadrunner-like.
Yellow-breasted chats and brown thrashers already are interesting species. And they may evolve into ever more intriguing kinds of birds, as can any other form of life on Earth.
Chats are far more often heard than seen because of the males' unique vocalizations and bizarre actions to establish nesting territories and attract mates for rearing offspring. Male chats utter whistles, clucks, toots and other strange notes, as well as pleasant songs. And male chats repeatedly rise from thickets in floppy, attention-getting flight, while singing, then drop back into the shrubbery.
With the genders being similar, chats are pretty birds, being olive-brown on top and bright-yellow below. They winter in Central America.
The chats' ancestry is the most interesting thing about them. They seem to be made of traits and parts leftover from other families of birds. They have been considered to be a New World wood warbler, but they are not a warbler. Currently, they are classified as a member of the blackbird/oriole family. Chats, however, are in a genus of their own because they are so unique. And over millenia, they may diverge into other species.
In many of their habits, chats resemble the mimidae family of birds, which includes mockingbirds, catbirds and thrashers. Chats skulk in the shadowed jungles of shrubs and vines like minidae. And they sing similarly to northern mockingbirds, including at night, and imitating other birds' sounds.
Chats often display the postures of North American cuckoos, kind of bent over with long tails drooping. But, apparently, chats are not members of the mimidae or the cuckoo families. Perhaps chats resemble those families because they share habitats- convergent evolution that shapes critters from different families into similar beings to cope with their environment in common.
Over future millenia, brown thrashers could be roadrunner-like, a species related to North American cuckoos. Those thrashers are built like roadrunners, but smaller, and have strong legs for running after prey, as roadrunners do.
I have seen brown thrashers, on foot, chasing after insect prey under thickets and across short-grass lawns. They always remind me of small, brown roadrunners.
Three closely related kinds of thrashers that live in deserts in southwestern North America, Leconte's, California and Crissal thrashers, are already roadrunner-like. Roadrunners, too, live in deserts where they run down lizards, snakes, mice and invertebrates. Those three kinds of thrashers seldom fly, but run fast enough, with their tails erect, to catch invertebrates and small snakes and lizards. These desert thrashers, through millenia, developed stronger, faster legs because the swiftest ones caught prey and survived, as roadrunners must have done. Maybe, some day, brown thrashers of the east will be more roadrunner-like.
Yellow-breasted chats and brown thrashers already are interesting species. And they may evolve into ever more intriguing kinds of birds, as can any other form of life on Earth.
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