During the past week, we’ve been exploring wooded slopes around the lower Susquehanna region in search of recently arrived Neotropical birds—particularly those migrants that are singing on breeding territories and will stay to nest. Coincidentally, we noticed a good diversity of species in areas where tent caterpillar nests were apparent.
The conspicuous nest of the Eastern Tent Caterpillar (Malacosoma americanum), a native species of moth. The first instar of the larval caterpillars hatch in early spring from egg masses laid on the limbs of the host tree by an adult female moth during the previous spring. Soon after they begin feeding on the host tree’s first tender shoots, these tiny, seldom-noticed larvae start communal construction of a silk tent to act as a shelter and greenhouse-like solar collector that will both provide protection from the elements and expedite their growth.The familiar last instar of the Eastern Tent Caterpillar is the most consumptive stage of the animal’s life. After feeding in the treetops, they will descend to the ground and seek a sheltered location to pupate. Adult moths emerge in several weeks to take to the air, mate, and produce eggs to be deposited on a host tree for hatching next year. The favorite host tree in forests of the Lower Susquehanna River Watershed: native Black Cherry.
Here’s a sample of the variety of Neotropical migrants we found in areas impacted by Eastern Tent Caterpillars. All are arboreal insectivores, birds that feed among the foliage of trees and shrubs searching mostly for insects, their larvae, and their eggs.
The Yellow-throated Vireo nests, feeds, and spends the majority of its time feeding among canopy foliage.The Eastern Wood-Pewee is a flycatcher found in mature woodlands. It feeds not only among the limbs and leaves, but is an aerial predator as well.The Northern Parula nests in mature forests along rivers and on mountainsides, particularly where mature trees are draped with thick vines.The Hooded Warbler (Setophaga citrina) is found among thick understory growth on forested slopes.The Ovenbird builds a domed, oven-like nest on the ground and forages in the canopy.The Kentucky Warbler (Geothlypis formosa) nests in woodland undergrowth, often near steep, forested slopes.The Worm-eating Warbler (Helmitheros vermivorum) nests among woody understory growth on forested hillsides.The Scarlet Tanager is often difficult to observe because of its affinity for the canopy of mature forest trees.
In the locations where these photographs were taken, ground-feeding birds, including those species that would normally be common in these habitats, were absent. There were no Gray Catbirds, Carolina Wrens, American Robins or other thrushes seen or heard. One might infer that the arboreal insectivorous birds chose to establish nesting territories where they did largely due to the presence of an abundance of tent caterpillars as a potential food source for their young. That could very well be true—but consider timing.
Already Gone- By the time Neotropical migrants arrive in our area, the larval stages of the Eastern Tent Caterpillar’s life cycle are already coming to an end. The nests that these native insects constructed to capture the energy of the springtime sun have allowed the larvae to exit and browse foliage when conditions were suitable, then return for shelter when they were not. While inside, the larvae could move among the chambers of their structure to find locations with a temperature that best suited their needs. Therein the solar heating and communal warmth sped up digestion and growth.Eastern Tent Caterpillar larvae are now in their bristly final-instar stage and the majority have already moved to the ground to each seek a place to pupate and metamorphose into an adult moth. Arboreal Neotropical birds have scarcely had a chance to feed upon them, and ground-feeding species seem to lack any temptation. As for the adult moths, they fly only at night and live for just one day, offering little in the way of food for aerial, arboreal, or ground-feeding birds.Having left arboreal environs, Eastern Tent Caterpillar larvae are now food for ground-feeding birds like our resident Wild Turkeys. They need only get past the bristly hairs on the caterpillar’s back and the foul taste that may result from its limited diet of cyanogenic Black Cherry leaves.The arboreal Yellow-billed Cuckoo (seen here) and its close relative the Black-billed Cuckoo (Coccyzus erythropthalmus) are the two species of birds in our area known to regularly feed on bristly tent caterpillars. But having just arrived from the tropics to nest, they’ll need to rely on other insects and their larvae as sources of food for their young.Final-instar Eastern Tent Caterpillars often defoliate Black Cherry trees before moving to the ground to pupate. Their timing allows them to feed on the fresh foliage while it is still young and tender, and to largely avoid becoming food for the waves of Neotropical birds that arrive in the lower Susquehanna basin in May.
So why do we find this admirable variety of Neotropical bird species nesting in locations with tent caterpillars? Perhaps it’s a matter of suitable topography, an appropriate variety of native trees and shrubs, and an attractive opening in the forest.
An American Redstart singing in a Black Cherry. Unlike others in the vicinity, this tree nestled among several very large Eastern White Pines showed no signs of tent caterpillar activity. It may be that for one reason or another, no adult female moth deposited her eggs on this particular tree. During our visits, Black Cherry was but one of the diverse variety of native trees and shrubs found growing on the sloping topography that created attractive habitat for the nesting birds we found. We happened to notice that a majority, but not all, of those Black Cherry trees were impacted by Eastern Tent Caterpillars.The end of the Eastern Tent Caterpillar’s larval surge may spell the end of their nests for the year, but it’s not the end for the Black Cherry and other host trees in the Prunus (cherry) and Malus (apple) genera. Because it’s still early in the season, they have plenty of time to re-leaf and many will still flower and produce fruit. Those flowers and foliage will attract numerous other insects (including pollinators) that benefit breeding birds.The Blue-winged Warbler inhabits shrubby breaks in the forest such as this utility right-of-way where Black Cherry trees have sprouted after their seeds arrived in waste deposited by fruit-eating (frugivorous) birds. Already attractive to a variety of insectivores, these openings soon lure egg-laying Eastern Tent Caterpillar moths to the cherry trees growing therein. Even in dense forest, a small clearing created by a cluster of dead trees makes good bird habitat and will sooner or later be visited by fruit-eating species that will inadvertently sow seeds of Black Cherry, starting yet another stand of host trees for Eastern Tent Caterpillars. It’s the gap in the forest that often attracts the birds, some of which plant the host trees, which sometimes entice Eastern Tent Caterpillar moths to lay their eggs.Adapt and Reuse- A Red-eyed Vireo visits an Eastern Tent Caterpillar nest……and ignores the few remaining occupants that could easily be seized to instead collect silk to reinforce its own nest.
Here in the Lower Susquehanna River Watershed, the presence of Eastern Tent Caterpillar nests can often be an indicator of a woodland opening, natural or man-made, that is being reforested by Black Cherry and other plants which improve the botanical richness of the site. For numerous migratory Neotropical species seeking favorable places to nest and raise young, these regenerative areas and the forests surrounding them can be ideal habitat. For us, they can be great places to see and hear colorful birds.
Our Lucky Break- This Scarlet Tanager descended from the treetops to feed on spiders in a small forest clearing.
In recent days, the peak northbound push of migratory birds that includes the majority of our colorful Neotropical species has been slowed to a trickle by the presence of rain, fog, and low overcast throughout the Mid-Atlantic States. Following sunset last evening, the nocturnal flight resumed—only to be grounded this morning during the pre-dawn hours by the west-to-east passage of a fast-moving line of strong thundershowers. The NOAA/National Weather Service images that follow show the thunderstorms as well as returns created by thousands of migrating birds as they pass through the Doppler Radar coverage areas that surround the lower Susquehanna valley.
Sterling, Virginia, Doppler Radar west of Washington, D.C., at 4:00 A.M. E.D.T. indicates a dense flight of northbound migrating birds located just to the south of the approaching line of rain and thunderstorms over the State College, Pennsylvania, radar coverage area. (NOAA/National Weather Service image)More northbound birds are indicated at 4 A.M. by the radar station located at Dover, Delaware… (NOAA/National Weather Service image)…and by the Mount Holly, New Jersey, radar site. (NOAA/National Weather Service image)Many of the migrating birds shown here over the Binghamton, New York, radar station at 4 A.M. probably overflew the lower Susquehanna region earlier in the night. (NOAA/National Weather Service image)And these birds over Albany, New York’s, radar station at 4 A.M. are mostly migrants that passed north over New Jersey and easternmost Pennsylvania last evening and during the wee hours of this morning. (NOAA/National Weather Service image)
Just after 4 A.M., flashes of lightning in rapid succession repeatedly illuminated the sky over susquehannawildlife.net headquarters. Despite the rumbles of thunder and the din of noises typical for our urban setting, the call notes of nocturnal migrants could be heard as these birds descended in search of a suitable place to make landfall and seek shelter from the storm. At least one Wood Thrush and a Swainson’s Thrush (Catharus ustulatus) were in the mix of species passing overhead. A short time later at daybreak, a Great Crested Flycatcher was heard calling from a stand of nearby trees and a White-crowned Sparrow was seen in the garden searching for food. None of these aforementioned birds is regular here at our little oasis, so it appears that a significant and abrupt fallout has occurred.
A White-crowned Sparrow in the headquarters garden at daybreak. It’s the first visit by this species in a decade or more.
Looks like a good day to take the camera for a walk. Away we go!
Along woodland edges, in thickets, and in gardens, Gray Catbirds were everywhere today. We heard and/or saw hundreds of them.During our travels, American Redstarts were the most frequently encountered warbler. Look for them in low-lying forested habitats.Many early-arriving Baltimore Orioles have already begun building nests. But widespread territorial fighting today may be an indication that some latecomer orioles became trespassers after dropping in on existing territories during the morning fallout.Red-eyed Vireos are difficult to see but easily heard in forested areas throughout the Lower Susquehanna River Watershed.If the oriole isn’t the showiest of the Neotropical migrants, then the Scarlet Tanager is certainly a contender…Listen for their burry, robin-like song in the treetops of mature upland forests.No woodland chorus is complete without the flute-like harmony of the Wood Thrush. Look and listen for them in rich forests with dense understory vegetation.The Eastern Wood-Pewee, another forest denizen, has an easy song to learn…a series of ascending “pee-a-wee” phrases interspersed with an occasional descending “pee-urr”. It was one of the few flycatchers we found today, but more are certainly on the way. Their numbers should peak in coming days.Yellow-rumped Warblers can be especially numerous during migration but tend to peak prior to the arrival of the bulk of the Neotropical species. This was the only “yellow-rump” we encountered today. The majority have already passed through on their way to breeding grounds to our north.If today you were to visit a streamside thicket or any type of early successional habitat, you would probably find this perky little warbler there, the Common Yellowthroat.The Yellow Warbler likes streamside thickets too. You can also find them along lakes, ponds, and wetlands, especially among shrubby willows and alders.While nowhere near the headquarters garden, we ran into another White-crowned Sparrow in less-than-ideal habitat. This one was in a row of trees in a paved parking lot.Not all songbirds migrate at night. The Bobolink is an example of a diurnal (day-flying) migrant. They’re currently arriving in hay fields that are spared the mower until after nesting season.While looking for Neotropical species and other late-season migrants, we also found numerous early arrivals that had already begun their breeding cycles. We discovered this Blue-gray Gnatcatcher on its nest in a Black Walnut tree……then, later in the day, we found this one in its nest, again in a Black Walnut tree. Note the freshly emerging set of leaves and flower clusters. With many tree species already adorned in a full set of foliage, open canopies in stands of walnuts we found growing in reforested areas seemed to be good places to see lots of migrants and other birds today. It’s hard to say whether birds were more numerous in these sections of woods or were just easier to observe among the sparse leaf cover. In either case, the nut-burying squirrels that planted these groves did us and the birds a favor.
There’s obviously more spring migration to come, so do make an effort to visit an array of habitats during the coming weeks to see and hear the wide variety of birds, including the spectacular Neotropical species, that visit the Lower Susquehanna River Watershed each May. You won’t regret it!
Wood Ducks arrived in February and March to breed in the lower Susquehanna valley. Soon after hatching in April or May, the young leave the nest cavity to travel under the watchful gaze of their ever-vigilant mother as they search for food along our local waterways. If you’re fortunate, you might catch a glimpse of a brood and hen while you’re out looking at the more than one hundred species of birds that occur in our region during the first half of May. Good luck!
“Waves” of warblers and other Neotropical songbirds continue to roll along the ridgetops of southern Pennsylvania. The majority of these migrants are headed to wintering habitat in the tropics after departing breeding grounds in the forests of southern Canada. At Second Mountain Hawk Watch, today’s early morning flight kicked off at sunrise, then slowed considerably by 8:30 A.M. E.D.T. Once again, in excess of 400 warblers were found moving through the trees and working their way southwest along the spine of the ridge. Each of the 12 species seen yesterday were observed today as well. In addition, there was a Northern Parula and a Canada Warbler. Today’s flight was dominated by Bay-breasted, Blackburnian, Black-throated Green, and Tennessee Warblers.
A Blackburnian Warbler at sunrise on Second Mountain.A hungry Blackburnian Warbler feeding on insects.Black-throated Green Warblers were a plentiful species among both yesterday’s and today’s waves of Neotropical migrants.A juvenile Black-throated Green Warbler.One of the scores of Tennessee Warblers seen on Second Mountain early this morning.Cape May Warblers were still common today, but not moving through in the numbers seen yesterday.A male Black-throated Blue Warbler.Compared to yesterday’s flight, lesser numbers of Magnolia Warblers were seen today.An adult male Wilson’s Warbler was a good find among the hundreds of birds swarming the ridgetop.This Nashville Warbler spent much of the day in the tangles of Mile-a-minute Weed surrounding the lookout.
Other interesting Neotropical migrants joined the “waves” of warblers…
Red-eyed Vireo numbers were higher than yesterday.This Warbling Vireo was found peering from the cover of the shady forest.A minimum of six Rose-breasted Grosbeaks were identified including the juvenile male seen here in first-fall plumage. Other good sightings were Scarlet Tanagers, an adult male Baltimore Oriole, and a dozen or more Ruby-throated Hummingbirds.Three Least Flycatchers were heard calling and seen chasing one another through a stand of dead timber on the south slope below the lookout.After the warbler flight settled, the task of counting migrating raptors commenced. Five Broad-winged Hawks including this one were tallied as they glided away to the southwest for a winter vacation in the tropics of Central and South America.
During the recent couple of mornings, a tide of Neotropical migrants has been rolling along the crests of the Appalachian ridges and Piedmont highlands of southern Pennsylvania. In the first hours of daylight, “waves” of warblers, vireos, flycatchers, tanagers, and other birds are being observed flitting among the sun-drenched foliage as they feed in trees along the edges of ridgetop clearings. Big fallouts have been reported along Kittattiny Ridge/Blue Mountain at Hawk Mountain Sanctuary and at Waggoner’s Gap Hawk Watch. Birds are also being seen in the Furnace Hills of the Piedmont.
Here are some of the 300 to 400 warblers (a very conservative estimate) seen in a “wave” found working its way southwest through the forest clearing at the Second Mountain Hawk Watch in Lebanon County this morning. The feeding frenzy endured for two hours between 7 and 9 A.M. E.D.T.
Tennessee Warblers (Leiothlypis peregrina) were very common among the migrants seen this morning on Second Mountain.An adult male Tennessee Warbler.A Nashville Warbler.A Chestnut-sided Warbler.Cape May Warblers were another common species during the morning flight.Magnolia Warblers were frequently observed as well.A Black-and-white Warbler exhibiting its nuthatch-like feeding behavior.A Blackburnian Warbler.Black-throated Green Warblers were numerous.A Bay-breasted Warbler.This was the only Wilson’s Warbler discerned among the hundreds of warblers seen in a “wave” on Second Mountain this morning.
Not photographed but observed in the mix of species were several Black-throated Blue Warblers and American Redstarts.
In addition to the warblers, other Neotropical migrants were on the move including two Common Nighthawks, a Broad-winged Hawk, a Least Flycatcher (Empidonax minimus), and…
At least half a dozen Scarlet Tanagers were in the treetops.And no less than 23 Ruby-throated Hummingbirds were counted cruising southbound past the lookout at Second Mountain Hawk Watch today.
Then, there was a taste of things to come…
One of 3 Red-breasted Nuthatches filling the air on the mountaintop with calls reminiscent of a toy tin horn. Will this summer’s forest fires in Canada prompt a significant invasion of this and other birds including winter finches in coming months? Time will tell.
Seeing a “wave” flight is a matter of being in the right place at the right time. Visiting known locations for observing warbler fallouts such as hawk watches, ridgetop clearings, and peninsular shorelines can improve your chances of witnessing one of these memorable spectacles by overcoming the first variable. To overcome the second, be sure to visit early and often. See you on the lookout!
Following a heavy nocturnal flight, an observer can often see Neotropical migrants in unusual places. For arboreal species looking to rest and feed after a long night of flying, large native trees in almost any location can be attractive. This Scarlet Tanager was found not in its typical habitat, a deciduous forest, but in an enormous Pin Oak (Quercus palustris) surrounded by manicured lawn.
There’s something in the air tonight—and it’s more than just a cool comfortable breeze.
(NOAA/National Weather Service image)
It’s a major nocturnal movement of southbound Neotropical birds. At daybreak, expect a fallout of migrants, particularly songbirds, in forests and thickets throughout the region. Warblers, vireos, flycatchers, thrushes, Scarlet Tanagers, and Rose-breasted Grosbeaks pass through in mid-September each year, so be on the lookout!
The southbound bird migration of 2020 is well underway. With passage of a cold front coming within the next 48 hours, the days ahead should provide an abundance of viewing opportunities.
Here are some of the species moving through the lower Susquehanna valley right now.
Blue-winged Teal are among the earliest of the waterfowl to begin southward migration.Sandpipers and plovers have been on the move since July. The bird in the foreground with these Killdeer is not one of their offspring, but rather a Semipalmated Plover (Charadrius semipalmatus), a regular late-summer migrant in the Lower Susquehanna River Watershed.Hawk watch sites all over North America are counting birds right now. The Osprey is an early-season delight as it glides past the lookouts. Look for them moving down the Susquehanna as well.Bald Eagles will be on the move through December. To see these huge raptors in numbers, visit a hawk watch on a day following passage of a cold front when northwest winds are gusting.Merlins were seen during this past week in areas with good concentrations of dragonflies. This particular one at Middle Creek Wildlife Management Area in Lancaster and Lebanon Counties……was soon visited by another.Check the forest canopy for Yellow-billed Cuckoos. Some local birds are still on breeding territories while others from farther north are beginning to move through.Ruby-throated Hummingbirds are darting through the lower Susquehanna valley on their way to the tropics. This one has no trouble keeping pace with a passing Tree Swallow.Nocturnal flights can bring new songbirds to good habitat each morning. It’s the best time of year to see numbers of Empidonax flycatchers. But, because they’re often silent during fall migration, it’s not the best time of year to easily identify them. This one lacking a prominent eye ring is a Willow Flycatcher (Empidonax traillii).During the past two weeks, Red-eyed Vireos have been numerous in many Susquehanna valley woodlands. Many are migrants while others are breeding pairs tending late-season broods.During mornings that follow heavy overnight flights, Blackburnian Warblers have been common among waves of feeding songbirds.Chestnut-sided Warblers are regular among flocks of nocturnal migrants seen foraging among foliage at sunrise.Scarlet Tanagers, minus the brilliant red breeding plumage of the males, are on their way back to the tropics for winter.While passing overhead on their way south, Bobolinks can be seen or heard from almost anywhere in the lower Susquehanna valley. Their movements peak in late August and early September.During recent evenings, Bobolinks have been gathering by the hundreds in fields of warm-season grasses at Middle Creek Wildlife Management Area.If you go to see the Bobolinks there, visit Stop 3 on the tour route late in the afternoon and listen for their call. You’ll soon notice their wings glistening in the light of the setting sun as they take short flights from point to point while they feed. Note the abundance of flying insects above the Big Bluestem and Indiangrass in this image. Grasslands like these are essential habitats for many of our least common resident and migratory birds.
After nearly a full week of record-breaking cold, including two nights with a widespread freeze, warm weather has returned. Today, for the first time this year, the temperature was above eighty degrees Fahrenheit throughout the lower Susquehanna region. Not only can the growing season now resume, but the northward movement of Neotropical birds can again take flight—much to our delight.
A rainy day on Friday, May 8, preceded the arrival of a cold arctic air mass in the eastern United States. It initiated a sustained layover for many migrating birds.
Bobolinks (Dolichonyx oryzivorus) in flocks of as many as fifty birds gathered in weedy meadows and alfalfa fields for the week.A Bobolink sheltering in a field of Sweet Vernal Grass (Anthoxanthum odoratum) during the rain on Friday, May 8th.Two of seven Solitary Sandpipers (Tringa solitaria) in a wet field on Friday, May 8. Not-so-solitary after all.Grounded by inclement weather, Rose-breasted Grosbeaks (Pheucticus ludovicianus) made visits to suburban bird feeders in the lower Susquehanna valley. (Charles A. Fox image)
Freeze warnings were issued for five of the next six mornings. The nocturnal flights of migrating birds, most of them consisting of Neotropical species by now, appeared to be impacted. Even on clear moonlit nights, these birds wisely remained grounded. Unlike the more hardy species that moved north during the preceding weeks, Neotropical birds rely heavily on insects as a food source. For them, burning excessive energy by flying through cold air into areas that may be void of food upon arrival could be a death sentence. So they wait.
A freeze warning was issued for Saturday morning, May 9, in the counties colored dark blue on the map. (NOAA/National Weather Service image)This radar image from 3:28 A.M. Saturday morning, May 9, indicates a minor movement of birds in the Great Plains, but there are no notable returns shown around weather radar sites in the freeze area, including the lower Susquehanna valley. (NOAA/National Weather Service image)To avoid the cold wind on Saturday, May 9, this Veery was staying low to the ground within a thicket of shrubs in the forest.This Black-throated Blue Warbler avoided the treetops and spent time in the woodland understory. He sang not a note. With birds conserving energy for the cold night(s) ahead, it was uncharacteristically quiet for the second Saturday in May.A secretive Northern Waterthrush (Parkesia noveboracensis) remained in a wetland thicket.A Scarlet Tanager (Piranga olivacea) tucks his bill beneath a wing and fluffs-up to fight off the cold during a brief May 9th snow flurry.In open country, gusty winds kept Eastern Kingbirds, a species of flycatcher, near the ground in search of the insects they need to sustain them.Horned Larks are one of the few birds that attempt to scratch out an existence in cultivated fields. The application of herbicides and the use of systemic insecticides (including neonicotinoids) eliminates nearly all weed seeds and insects in land subjected to high-intensity farming. For most birds, including Neotropical migrants, cropland in the lower Susquehanna valley has become a dead zone. Birds and other animals might visit, but they really don’t “live” there anymore.Unable to find flying insects over upland fields during the cold snap, swallows concentrated over bodies of water to feed. Some Tree Swallows may have abandoned their nests to survive this week’s cold. Fragmentation of habitats in the lower Susquehanna valley reduces the abundance and diversity of natural food sources for wildlife. For birds like swallows, events like late-season freezes, heat waves, or droughts can easily disrupt their limited food supply and cause brood failure.For this Barn Swallow, attempting to hunt insects above the warm pavement of a roadway had fatal consequences.Another freeze warning was issued for Sunday morning, May 10, in the counties colored dark blue on this map. (NOAA/National Weather Service image)This radar image from 4:58 A.M. Sunday morning, May 10, again indicates the absence of a flight of migrating birds in the area subjected to freezing temperatures. Unlike migrants earlier in the season, the Neotropical species that move north during the May exodus appear unwilling to resume their trek during freezing weather. (NOAA/National Weather Service image)On Sunday evening, May 10, a liftoff of nocturnal migrants is indicated around radar sites along the Atlantic Coastal Plain and, to a lesser degree, in central Pennsylvania. The approaching rain and yet another cold front quickly grounded this flight.After a one day respite, yet another freeze warning was issued for Tuesday morning, May 12. (NOAA/National Weather Service image)And again, no flight in the freeze area. (NOAA/National Weather Service image)The freeze warning for Wednesday morning, May 13. (NOAA/National Weather Service image)And the nocturnal flight: heavy in the Mississippi valley and minimal in the freeze area. (NOAA/National Weather Service image)The freeze on Thursday morning, May 14. (NOAA/National Weather Service image)At 3:08 A.M. on May 14th, a flight is indicated streaming north through central Texas and dispersing into the eastern half of the United States, but not progressing into New England. (NOAA/National Weather Service image)The flight at eight minutes after midnight this morning. Note the stormy cold front diving southeast across the upper Mississippi valley. As is often the case, the concentration of migrating birds is densest in the warm air ahead of the front. (NOAA/National Weather Service image)
Today throughout the lower Susquehanna region, bird songs again fill the air and it seems to be mid-May as we remember it. The flights have resumed.
Indigo Bunting numbers are increasing as breeding populations arrive and migrants continue through. Look for them in thickets along utility and railroad right-of-ways.Common Yellowthroats and other colorful warblers are among the May migrants currently resuming their northward flights.The echoes of the songs of tropical birds are beginning to fill the forests of the lower Susquehanna watershed. The flute-like harmonies of the Wood Thrush are among the most impressive.Ovenbirds are ground-nesting warblers with a surprisingly explosive song for their size. Many arrived within the last two days to stake out a territory for breeding. Listen for “teacher-teacher-teacher” emanating from a woodland near you.
