The northern half of Maine contains 10 million acres of forest with no paved roads, towns or other significant development. These unorganized territories represent a huge amount of habitat for the Maine biota.

Most of this land is commercial forest. The owners of this property regularly harvest trees to provide the timber and paper we all depend on. The timber harvesting provides a significant number of jobs in northern Maine.

An alarm was sounded in 1989 when John Terborgh published his book, Where Have All the Birds Gone. The Breeding Bird Survey, begun in 1966, was showing declines in many neotropical migrant birds.  John Hagan, a Research Biologist at the Manomet Bird Observatory in Massachusetts, was one of the organizers of an international symposium in 1989 to examine the decline of the neotropical migrants. John was inspired to undertake a study in the Maine North Woods to examine the impact of forestry on bird diversity and abundance.

John established collaborations with forest ecologists for the largest forest companies in the Moosehead Lake region. These partnerships were cooperative as all stake-holders were interested in the impacts of current logging practices on birds. The forest owners provided significant funding for the project and granted John’s team access to these privately owned lands.

Field work was done in the summer from 1992 through 1994. The field team used the point-count method for their censuses. A point-count is conducted by standing at a fixed point and then counting all birds heard and seen within 10 minutes in a 50-m radius. A detailed vegetation survey was done at each sampling point. John’s team did point-counts at 387 points.

Stands of different ages support a characteristic suite of birds. For instance, newly clear-cut areas support some species like Lincoln’s Sparrows and White-throated Sparrows, followed a few years later by Mourning Warblers and Chestnut-sided Warblers .

The major advance of the study is the measurement of actual density of those species. Since the timber companies maintain a detailed map of the age of all the stands on their property, estimating the total number of a particular bird species is facilitated.

Impelled in part by a 2019 paper that reported that 30% of North American birds have perished since 1970, John decided that repeating the earlier study 30 years later would have value.

John procured funding and field work was done in 2021 and 2022, again with the cooperation of the timber companies. Field technicians did point-counts at 422 points in the Moosehead region over those two summers. The preliminary report of the project has just been released.

The ownership of most of the forests changed between the early 1990s and 2021-2021. Logging practices had changed as well. Clear-cutting has been nearly abandoned in favor of shelterwood cutting. In this technique, about two-thirds of a stand is cut and then the remaining third is cut ten years later when new trees have begun to grow in the understory over those ten years.

With all the bad news about declining bird populations, the 2021-2022 data provided some positive news. Forest management practices have improved the population trajectory of many birds. Forty-two species are more abundant now than they were in 1992-1994 and only 19 species show a decline. American Redstarts increased in density three-fold and Black-and-white Warblers doubled. Magnolia Warblers showed the sharpest decline, about a 33% loss.

John takes a holistic view of the North Woods. Rather than focusing on a single clear-cut or shelterwood cut, he envisions the industrial forest as a shifting mosaic. Older forests are always present but as they are cut, other areas harvested earlier grow to replace the habitat. The one forest type that is underrepresented is the 100-200 year-old mature forest. Timber companies maximize their profits by harvesting 50 to 70-year old tracts of forest.

We know that nearly all groups of birds have been declining over the past 50 years. Solid estimates exist of a 30% decline in bird populations since 1970.

The American Bird Conservancy recently published their estimates of the annual number of bird deaths by source, all of which are associated with direct or indirect human impacts. Nine threats are identified that each result in the death of at least 500,000 each year.

Mitigating some of these causes of avian death are systemic problems and individual efforts are not very effective. A million birds a year die each year by being trapped in mines and wastewater pits. 680,000 birds perish from collisions with wind turbines.

Lead poisoning takes the lives of 1.2 million birds a year. Many of these deaths are waterfowl that ingest lead pellets from the sediment of water bodies to use in their gizzards to grind food. Replacement of steel shot with lead shot in shotgun shells is helpful.

Birds are disoriented by the lights on tall communication towers, particularly during nocturnal migration. Those collisions kill 6.8 million birds a year. Collisions with and electrocution by power lines kill 36.5 million birds a year. Again, these deaths are a consequence of the ways humans alter our environment for our own comfort.

Although we have moved away from some harmful pesticides like DDT, chemicals to control agricultural insect pests pose dangers to other animals. The bird toll of pesticides is 72 million birds a year. These deaths are unintended but still add to the toll of bird deaths.

Collisions with cars take the lives of 200 million birds a year. Those deaths are hard to reduce with our lifestyles dependent on car transportation.

An estimated 600 million birds die each year from collisions with windows. Birds either see a reflection of their habitat in the windows during the day or perceive a lighted room beyond a window as a tunnel at night. Significant improvements in reducing reflectivity have been made (see: https://rb.gy/si1pe). We can make a difference here as individuals.

The most devastating source of bird mortality is cat predation. Cats kill 2.4 billion birds each year in the United States! That is twice the mortality of the other eight mortality sources combined.

We need to realize that cats are not part of the native fauna of North America. Rather, they represent domesticated cats that arose by artificial selection in western Asia, likely derived from the African wildcat.

Cats accompanied Columbus and were on the Mayflower. However, they did not become popular pets until the end of World War I. Today, our pet cat population is estimated at 85 million cats, about half of which spend some time outdoors.

To reduce the impact of cat predation, cats should be kept as indoor-only pets. Cats are simply too efficient at capturing birds. Sure, cats enjoy being outside but a risk-reward analysis to me comes down clearly on the indoor cat solution. People who insist on letting their cats go outside should at least put a bell or a cat bib (a Google search will yield lots of cat bib hits) on their cat. Bird feeders and bird baths should be maintained high enough to deter a jumping cat.

Pet cats are only part of the problem. There are 60-100 million feral cats on the loose. On average, a feral cat kills three times as many birds a year as a free-ranging pet cat. There are some animal rights groups that are capturing feral cats to neuter them to at least keep the population from growing. Other people favor exterminating feral cats. As an unabashed cat-lover, I find these conversations difficult but necessary as our bird populations continue to decline. Imposing the deaths of 2.4 billion birds a year from a source that was barely significant 100 years ago should give us all pause.

Birding

Herb Wilson

The next few weeks represent the pinnacle of bird concerts. Male songbirds are singing vigorously and often to attract a mate and to fend off other males seeking to usurp their territory.

Learning to identify the various songs and calls of birds is a joy and a worthy goal. At this time of year, most expert birders identify 90% of the birds they encounter by sound. The variety of bird sounds means that one’s education in auditory identification is never done.

There are tons of resources to allow you to improve your identification of bird sounds. I wrote favorably of the app Merlin, produced by the Cornell Laboratory of Ornithology. This app will identify sounds (and photos) of birds. The app is free for download for iPhones and Android phones.

Another free app is The Audubon Bird Guide, produced by the National Audubon Society. Multiple recordings of vocalizations and photographs of different plumages provide a valuable learning tool.

The AllAboutBirds.org website offers many recordings of bird vocalizations with useful text.

Close listening to bird songs often rewards the listener with a deeper appreciation of bird songs. I’ll describe some variations of Maine bird song that I find fascinating.

You need to be an early riser to appreciate the first three examples. The Eastern Phoebe’s song is a familiar, insistent fee-bee song. But early in the morning, males throw in an extra syllable, fee-buh-bee. Why? We have no idea, but I love listening for that variation.

We also don’t understand the early morning variations of two other common nesting birds. The American Robin sings a carol of two- and three-note phrases: cherrily, cheer up, cherrily, cherrily, cheer up, cheer up. Early in the day, males throw in an extra sibilant phrase, effectively described as hissely. Listen for that phrase when the robin outside your house starts singing at four AM.

The Chipping Sparrow song is a dry trill, given from a perch in a tree. Back in the days before telephones had ring tones, I met a woman who called Chipping Sparrows the telephone birds because she always felt like she needed to answer her phone when a sparrow was singing its regularly spaced trills.

Shortly after dawn, chipping sparrows alter their singing behavior. Males from adjacent territories will fly down to a common area and sing from the ground. Rather than a long trill, the songs are short, staccato-like bursts. Whatever it takes to impress a female.

The Hermit Thrush is one of our most accomplished singers. The song consists of a sustained whistle followed by a number of flute-like phrases. The song is haunting and hopelessly beautiful. Listen for the change in pitch of the whistle between songs. The pitch alternates between a low pitch and a high pitch in consecutive songs. Again, we have no clue as to why this variation occurs.

A birder hears the distinctive song of an American Redstart: a series of thin notes, ending in a strongly accented note. She looks in the trees to try to see the songster, expecting a black bird with orange in the wings and tail. But no. The singing bird is gray with yellow in the wings and tail. Do female American redstarts sing?

No, this singing bird is a second-year male whose plumage mimics female plumage. We are seeing a phenomenon called delayed-plumage maturation. We know that older males tend to be more successful in attracting mates and first-timers often fail to gain a territory.

So, a second-year bird uses stealth to try to mate with a female. The female-like plumage does not raise the ire of a territorial male and its song alerts a female who is up for an extra-pair affair that he is available.

Delayed plumage maturation also occurs in Baltimore Orioles and Red-winged Blackbirds.

We have some species in which females sing as well as males. Northern Cardinals, Song Sparrows, Baltimore Orioles and House Finches are examples.

Last November, my wife and I and six friends had a wonderful two-week birding trip with Rockjumpers to northern Ecuador. The trip had been postponed twice because of COVID. At long last, we flew to Ecuador on Halloween on what proved to be an extraordinary trip.

The trip consisted of two legs, the first to the west of the Andes mountains in the Chocó region. This area was dominated by cloud forests. The second half began at the crest of the northern Andes and moved eastward to lower altitude, almost reaching the upper limit of the Amazonian rain forest.

I was able to see or hear 372 species of birds. This total included 49 hummingbird species and 56 species of tanagers.

To give a taste of the trip, I’ll describe some of the most memorable sightings and habitats. For a full list of all species with my pictures of 113 species, visit my eBird report: https://ebird.org/tripreport/86127

At the Bellavista Lodge, a pair of Masked Trogons and a Blue-winged Mountain Tanager delighted us right after breakfast. We visited a nearby reserve to see a pair of spectacular Plate-billed Mountain Toucans. We got amazing looks at a pair of Crested Quetzals as well.

From the Mindo area, we got an early start to drive to Refugio de Paz de las Aves, a reserve operated by brothers Ángel and Rodrigo Paz. Right at dawn, we hiked down to a blind from which we saw a dozen male Andean Cock-of-the-rocks displaying on tree branches with a few females comparison shopping. The males are bright red above, black below with gray wing patches. Absolutely stunning!

With lightness in our steps, we hiked back up the trail to look for antpittas. These are secretive ground birds with scarcely a tail at all. Think of an egg standing on two sticks.

Ángel and Rodrigo have perfected a way to see antpittas. They put earthworms on a fallen log and then call in an antpitta using imitations of their calls, Spanish commands (“venga, venga, venga” (“come, come, come”)) and tossing pebbles to make a sonic pathway for the antpitta to the earthworms. All we had to do was sit and wait.

We were able to get astonishing views of five species of ant-pittas including the Giant Antpitta. What a treat! We know why the Paz brothers are known as the antpitta whisperers.

I was particularly excited to visit the paramo habitat, the landscape above tree line. We stopped first at Tambo Condor and quickly found some Andean Condors soaring. These birds have wingspans of 10.5 feet and can weigh up to 33 pounds. They are the largest flying birds in the world.

Bushes around the visitor’s center attracted some Giant Hummingbirds. With a length of nine inches (about the length of a Northern Cardinal), Giant Hummingbirds are by far the largest hummers in the world.

Continuing to an elevation of nearly 15,000 feet, we got to see a cryptic Rufous-bellied Seedsnipe, a shorebird that looks more like a grouse. It was tough work to hike up from the parking lot in that thin air to see the seedsnipe.

Descending to the east, we spent a couple of nights at the Guango Lodge. We watched the many hummingbird feeders there, hoping for a Sword-billed Hummingbird. Suddenly one appeared! Its bill is astounding. It can be up to 4.7 inches long, nearly the length of the bird’s 5.1-inch body. No other bird has such a long bill relative to its body length.

We spent the better part of an afternoon along a white-water stream on a successful hunt for Torrent Ducks.  The female has red underparts and a gray head. The male has a striking head with black and white stripes and a gray body.The most unusual aspect of these ducks is the massive size of their feet, the better to swim effectively against the currents.

The glorious spring migration has just concluded. The arrival of the last Black-billed Cuckoos and Nelson’s Sparrows by June 10 signals the end of the spectacle. Now we can tune our ears to the various songs our nesting birds are making.

The spring arrival of our migratory breeding birds, bedecked in their colorful breeding plumage, stands alone as an awesome phenomenon. But this period of movement is made even more exciting by the appearance of vagrant species, species that generally do not nest in Maine. This spring has been one of the most exciting ones in my memory for vagrants.

How do these birds end up out of place in Maine? The answer is complicated, and we have much to learn about the reasons vagrants show up in unexpected places.

Some vagrants arrive because of overshooting. Such birds breed to our south. Either because of navigational error or strong winds, these birds appear briefly in our state, realize their error, and presumably head back south to seek a mate.

Three good examples are a Yellow-throated Warbler in Sanford on May 2, a Worm-eating Warbler on Monhegan Island on May 17 and a Hooded Warbler at Fort Foster on May 10. The northern limit of nesting is Massachusetts for the first two species and Pennsylvania for Hooded Warbler.

Other examples include Yellow-crowned Night-herons that appeared at Dyers Point, Portland, and Stratton Island. They breed regularly as far north as Connecticut.  Summer Tanagers breed as far north as Pennsylvania; one in Pembroke on May 3 had overshot.

Several White-eyed Vireos appeared in Maine; they do not nest north of Connecticut.

Multiple Black Vultures appeared in Maine. Their current northern nesting limit is Massachusetts.

We had at least two records of Chuck-will’s-widow this spring in Hancock County. Their nesting limit is currently Long Island.

We need to keep an eye on these vagrants that breed relatively close to Maine. Vagrants may decide that Maine would be a fine place to breed, particularly with global warming effects. The gradual movement of vagrants into Maine in the past 40 years has led to the establishment of Turkey Vultures, Red-bellied Woodpeckers, Tufted Titmice, Carolina Wrens and House Finches as regular breeders. Who will be next?

We had other vagrants from the eastern United States that nest well to our south. These birds overshot spectacularly.  A Mississippi Kite at Cape Neddick on May 13 was over a thousand miles north of its breeding range.

A White Pelican was spotted in Portland on May 15. This species mostly breeds on freshwater lakes in western North America although some non-breeders occur along the Gulf coast.  

Perhaps the most exciting vagrant this spring was the Crested Caracara, a ground-foraging falcon. They nest in central Florida and Texas. We have one prior record of the species in Maine in August and September, 2014. Three appeared in Maine this spring between May 23 and 25 in Fryeburg, Cape Elizabeth, and Round Pond.

Maine had several vagrants from the western part of North America his spring. I expect that navigational errors explain these remarkable records. These records include a Rufous Hummingbird in Frankfort on May 1, a Harris’s Sparrow in late April in Turner, and White-winged Doves in Farmington and Pemaquid on May 24.

Coastal birds often show high levels of vagrancy. This spring saw several records of Caspian Terns along the coast, as far as Washington County, a Brown Pelican in Kittery, a Black-necked Stilt in Scarborough, and several White-eyed Ibises in southern coastal Maine.

Finally, there are head-scratchers. What was an arctic-breeding King Eider doing in Maine at Fortunes Rock in late May? How about a Eurasian Golden-plover in Scarborough on May 21? A Pacific Loon at Ferry Beach on May 2?

We may not understand why these vagrants arrived in Maine, but it is surely a thrill to see them.

Several people in the first half of May told me about male Scarlet Tanagers in their breeding finery visiting their sunflower seed feeders. These birds usually glean caterpillars and other insects from leaves in the upper part of the forest canopy. They rarely visit feeders in June and July.

What’s going on? The explanation is that caterpillars are hard to find in early May so the tanagers need to find alternative food until the trees fully leaf out with the insect herbivores following thereafter.

These observations point to a more general point about spring migration. Males are on the horns of a dilemma. A male needs to arrive as soon as possible to stake out a good territory. We know there are satellite males around in the summer, looking to sneakily mate with some other male’s mate. Arriving early is a way to guarantee one of the limited nesting territories.

But the downside of arriving early is that there may be insufficient food to allow an eager male to survive long enough to mate. So, males need to find an arrival time that is just right, balancing the competing pressure of having enough food and securing a territory.

How do migrants know when to arrive? The answer is complicated and requires that we distinguish between short-distance migrants and long-distance of neotropical migrants.

Our short-distance migrants overwinter south of us in North America. Yellow-rumped Warblers are abundant in the winter along the coast of the mid-Atlantic and southern states. Red-winged Blackbirds winter broadly across the southern half of the United States. Some of our American Robins may migrate only as far south as Massachusetts to spend the winter.

Using daily temperature records for April and May from the National Oceanographic and Atmospheric Administration, I looked for broad-scale patterns of temperature variation. Does a warm April in New Jersey predict a warm April in Maine?

I found that the states between Maine and Delaware behaved as a unit. All points within this broad area showed correlated warm or cool springs in a given year.

These patterns provide a useful cue for the spring migration of birds. A bird in Pennsylvania may arrive when insects are hard to find so delaying a few days is a good strategy. By following spring north, birds will arrive on their breeding grounds when food is starting to become adequate.

Long-distance migrants, on the other hand, have no easy way to know what the weather is like in North America. Ruby-throated Hummingbirds in Costa Rica, Bobolinks in Argentina or Blackburnian Warblers in Ecuador rely on changes in daylength.

Different species of neotropical migrants arrive on different schedules so the critical daylength varies. Since day lengths at this time of year are growing shorter south of the equator, Bobolinks respond to decreasing daylength.

Once the critical photoperiod is reached, migratory birds manifest a behavior called migratory restlessness. This behavior was first documented in captive birds who repeatedly tried to move in a northward direction.

The reliance of short-term migrants on current weather conditions versus the reliance of neotropical migrants on photoperiod has some important implications for climate change. One study has shown that  short-term migrants are arriving now about 13 days earlier on average than they did from 1950-1999. Long-distance migrants are arriving only about four days early.

The threat that looms for long-distance migrants is that a variety of biological events like leaf-out, caterpillar emergence and flowering are occurring earlier. So, the photoperiod cue for migration causes neotropical migrants to arrive after the peaks of these biological events. These birds are arriving late to the party when most of the food is gone. The most striking example of this asynchrony of events involves the Pied Flycatcher in Europe. These birds winter in Africa and breed broadly across Eurasia. The adults feed their nestlings caterpillars. Earlier leaf-out and caterpillar emergence means that the flycatchers arrive to find caterpillars hard to find. The pied flycatcher population in Europe has declined by 44% in the past 22 years.

Any naturalist keeps eyes and ears open when outside. A naturalist might note that there sure are a lot of Turkey Vultures this spring. Or, wow, the Tree Swallows came back early this spring. Or, I hardly see Rose-breasted Grosbeaks anymore.

These observations have value, but each is a single data point and may not indicate a general trend. To really detect patterns in nature, we need many observations to get a clear picture. Strong baseline data allow us to gauge changes in population numbers, geographic range, migration, and reproductive success.

Acquiring such information is beyond the capacity of any researcher, no matter how energetic. Rather, researchers have harnessed the power of interested naturalists to gather data. The term, citizen science was coined in 1989 to describe projects that rely on the collective contributions of amateur scientists.

A just completed example of citizen science is the Maine Bird Atlas, a five-year study to document the geographic distribution of breeding birds and wintering birds in Maine.

 This project had contributions from over 3,000 volunteers who submitted over 125,000 checklists. That’s the power of a crowd.

The Maine Atlas team is already working on finalizing maps, analyzing the data, and writing the species accounts so look for a book in the next two or three years.

This project is the second atlas of Maine birds. From 1979 until 1983, volunteers produced the first breeding bird atlas for Maine. This project involved far fewer volunteers and had a much coarser geographic focus. But this project provided the baseline for use in the newer atlas to consider changes in breeding ranges of our birds.

I usually grin a bit when I hear the term citizen science. Yes, the phrase is only 34 years old but projects relying on volunteer naturalists are much older. The grande dame of citizen-science projects in North America must be the National Audubon Society Christmas Bird Count (CBC).

The CBC was begun in 1900 and is still going strong. Sampling the same circle within a 15-mile radius each December allows us to gauge changes in winter bird distribution and abundance.

In the 1950’s and early 1960’s, birders were noting that many of our breeding species seemed less abundant. Those observations coincided with the publication of Silent Spring by Rachel Carson, alerting us to the dangers of DDT and other organic pesticides. Still, hard data were needed to establish that those individual observations indicated broader declines.

In 1966, the first Breeding Bird Surveys (BBS) were begun. Conceived by the U. S. Fish and Wildlife Service biologist, Chan Robbins, these surveys involve the sampling of 50 stations along a 25-mile route. Each stop is sampled for three minutes with all birds heard and seen tallied.  The BBS data have shown that many neotropical migrants were indeed showing precipitous declines. This continuing project allows us to see the distribution and abundance of all breeding species across North America. The BBS is also a citizen-science project begun before citizen science was a phrase.

The Maine Department of Inland Fisheries and Wildlife, in collaboration with other Maine scientists, have conducted other citizen-science atlas projects. The first amphibian and reptile atlas was published in 1999 and a second atlas is now underway.

Atlases for some groups of insects have been completed. The Maine Dragonfly and Damselfly Survey was conducted between 1995 and 1999. The Maine Bumble Bee Survey took place from 1999 through 2006. The Maine Butterfly Survey relied on field work from 2005 through 2017. This atlas will be published in October by the Cornell University Press.

If you are interested in participating in a citizen-science project, consider joining the Firefly Atlas Project. Who doesn’t love fireflies? Records are gathered by capturing fireflies, photographing them, and noting their flashing pattern. The fireflies can then be released. Find more information here: https://www.fireflyatlas.org/  Maine only has 15 species of fireflies, so the project provides a great chance to learn most of Maine’s fireflies.

This post concerns the plight of shorebirds. Shorebirds are a convenient grouping of bird families that generally include wading birds that frequent the shorelines of oceans, lakes, and flowing water.

Shorebirds include sandpipers, plovers, oystercatchers, avocets, stilts, and phalaropes as well as other birds like the ibisbill and painted snipes that don’t occur in North America. Most shorebirds are long-distance migrants, spending the northern winter as far south as Tierra del Fuego in Chile.

We have some nesting species of shorebirds in Maine like Killdeer, Spotted Sandpiper, Wilson’s Snipe, and American Woodcock. However, most shorebirds breed at high latitudes on the arctic tundra. Most shorebirds on the list of Maine birds are passage migrants; we see them briefly in the spring and fall as they pass through to and from the tundra.

Shorebird migration differs in an important way from landbird migration. On migration, landbirds may end a migratory leg anywhere along their migration route. However, shorebirds tend to use traditional stop-over areas. Their migrations are therefore often point-to-point routes.

These stop-over areas are food-rich areas that permit shorebirds to fatten to replace their fuel stores so they can continue their migration. For brief periods of time, most individuals of some species can be found at a single site. Examples include Delaware Bay in late May when Red Knots stop to feed on horseshoe crab eggs and the upper Bay of Fundy where Semipalmated Sandpipers gather in August and September to feed on small crustaceans in the expansive intertidal mudflats. Obviously protecting these stop-over areas is of paramount importance.

The Western Hemisphere Shorebird Reserve Network was established with the cooperation of biologists throughout North America, Central America, South America, and islands of the Caribbean. This network has no legislative power but serves to educate politicians, environmental managers, and naturalists about important stop-over areas for shorebirds in the Western Hemisphere. Currently 19 countries are participating and 115 stop-over areas are identified as critically important.

A recent article in the journal Ornithological Applications provides an alarming assessment of shorebird populations in the Western Hemisphere. Paul Smith and nine co-authors (a mix of Canadian and American biologists) consider the population status of 28 shorebird species.

The study relied on shorebird abundance data in the fall from 1980 to 2019. Several monitoring programs (the International Shorebird Survey and two Canadian shorebird surveys) provided the bulk of the data.

The authors found that 26 of the 28 shorebird species for which sufficient data were available showed declines over the 39-year period. Nineteen species showed uniformly negative declines across all survey areas.

This pattern is distressing enough but is exacerbated by the finding that the rate of decline is accelerating. Comparing the current three-generation period (10-23 years depending on the species) with the previous three-generation period showed that 18 species have stronger declines in the more recent period.

Over half of the species analyzed had declines of 50% or more over the study period. This rate of decline qualifies these species as threatened under current international guidelines.

Staging areas between North Carolina and Nova Scotia show the strongest declines of shorebird abundance. Staging areas along the Gulf coast and in the center of North America show negative but less severe declines.

What species seem to be most in danger? Red Knots and Hudsonian Godwits head the list. Both species lost 90% of their numbers over the last 39 years. Others with precipitous declines are Short-billed Dowitchers, Long-billed Dowitchers, Dunlin, Lesser Yellowlegs, Whimbrel, Stilt Sandpiper and Ruddy Turnstone. The only two species showing an increase are Marbled Godwit and Willet.

What are we to do? Interventions require targeted efforts based on the biology and migration route of each species. The success of the American Oystercatcher project gives hope. Recovery efforts were started in 2010 and by 2019, a 23% increase in oystercatchers was realized.

Earth Day, April 22, is a red-letter day for me each spring. The brainchild of Senator Gaylord Nelson of Wisconsin, the first Earth Day occurred in 1970. As a high schooler, I was excited by this new day of significance and worked with a few other students to promote the day at our school. Who knew how important this day would become as a flashpoint for environmentalist and conservation?

So many activities were planned on Earth Day that April has been designated Earth Month to spread those activities around. April, a time of renewal and growth in the northern hemisphere, is a particularly appropriate time.

In the 1970’s, a catch phrase in the environmental movement took hold: Think Globally, Act Locally. There is much to recommend this pithy phrase. We all can recite a litany of how we can help protect Mother Earth locally in our daily lives. Recycle paper and metal. Cut down on our use of electricity. Install solar panels. Buy local vegetables and fruits. Plant trees.

Think Globally is an acknowledgement of the fact that we share one atmosphere. Water and nutrient cycles are global in scope.

However, I think this phrase is overly simplistic. The underlying assumption is that if everyone can improve their own patch of the earth, collectively world environmental health will be assured.

To me, the catch phrase embodies two extremes: our backyard and the globe. But we see interconnections between parts of the globe that fall in between. As environmentalists, we need to be mindful of these relationships to be effective stewards of our natural world.

Here’s an example. The American Redstart is a common warbler, nesting broadly across North America. This species is a neotropical migrant, wintering in the Caribbean, Central America, and South America. Most of the redstarts nesting in New England overwinter in the Greater Antilles

The research I will describe here was done by Peter Marra as a part of his doctoral research at Dartmouth College about 25 years ago. Peter studied overwintering American Redstarts in Jamaica, one of the Greater Antilles. The warblers are territorial on their wintering grounds, with each individual, male or female, maintaining an exclusive feeding territory.

Older male redstarts dominate food-rich mangrove habitats while females and younger males must make do with territories in drier, second-growth scrub habitat with less food.

Redstarts in wetter habitats gained weight through the winter while those in scrub habitat lost weight.

Peter sought to determine if wintering habitat had an effect of nesting success. Did individuals wintering in mangrove habitats have better nesting success than those in drier habitats?

Because the American Redstart population is nearly 40 million birds, the odds of finding a nesting bird in North America banded in Jamaica is essentially zero. But Peter had a clever way of gauging the winter provenance of breeding birds.

Most chemical elements occur in several forms, called isotopes. They differ by the number of neutrons in their nucleus. Carbon provides a useful tool because two isotopes, carbon 12 and carbon 13 (with one extra neutron) are common and stable. The proportion of the two isotopes varies in plants among different habitats.

The proportion of carbon 12 to carbon 13 is passed up the food chain to herbivorous insects to birds. So, a blood sample of a redstart tells us in which type and quality of habitat a bird overwintered. Peter did just that by capturing redstarts shortly after their arrival on their breeding grounds and taking a blood sample.

Redstarts arriving earliest had wintered in the mangrove forest. These birds had the best choice of territories and mates. Birds with blood signatures indicating wintering in scrub habitat arrived later with less weight and other signs of poor physiological condition. Those birds had to take lower quality territories.

So, we see an interconnection between wintering grounds and breeding grounds that is not on a global scale, complicating conservation efforts. Sometimes, acting locally is not enough.

One of my favorite spring-time migrants is a delightful sprite, the Ruby-crowned Kinglet. The average arrival date in Maine is around Tax Day and a few will arrive by the first of April.

Ruby-crowned Kinglets spend their winter in the southern parts of the United States into Mexico. We think of them as a short-distance migrant because they do not leave our continent, flying over open ocean, to get to South America as Bobolinks or Blackburnian Warblers do.

We have a second kinglet in state, the Golden-crowned Kinglet, that is a year-round resident. These two closely related species show some rather striking differences. But first, let’s look at the similarities.

These two species are the smallest songbirds we have in the state. Each tips the scale at about seven grams, less than the weight of three pennies. The Black-capped Chickadee has twice the mass of a kinglet. The only smaller bird in the state is the Ruby-throated Hummingbird.

The kinglets belong to the genus Regulus. Translated from the Latin, Regulus means small king. I think you will agree that kinglet is a cooler translation.

Kings wear crowns and that is the case for both kinglets. The Ruby-crowned Kinglet males have a crown of red feathers that are usually obscured by gray feathers. The crown of both male and female Golden-crowned Kinglets has a couple of black stripes separating a central lemon-yellow patch. Those yellow feathers hide metallic orange feathers.

These crowns are very important in social signaling. When a kinglet becomes aggressive toward another kinglet, it will expose its red or orange feathers, signaling its willingness to fight.

In the summer, both kinglets are primarily insect-eaters. Like most of our other leaf-gleaning insectivores like warblers, vireos and tanagers, ruby-crowns migrate in the fall.

We do have some year-round species like chickadees, nuthatches and Tufted Titmice that primarily eat insects in the summer but switch their diet to seeds to get through the winter.

The golden-crowned kinglet has a different strategy. It is a resident species but does not give up its meat-eating ways in the winter. Instead, it forages for insects and spiders that have allowed their bodies to freeze in a controlled way to survive the winter. The kinglets forage at the tips of conifer branches and underneath bark scales on those conifers where the invertebrates are overwintering.

The ability of Golden-crowned Kinglets to survive the winter astounds me. Small warm-blooded animals are greatly disadvantaged by geometry. The laws of geometry result in small objects having a high surface to volume ratio. Heat is lost across the surface and must be replaced by the cells in the volume of body. The modest number of cells in the body of a kinglet must work hard to replace the heat lost across the relatively large surface. Small birds and mammals are really living on the edge during the winter.

To reduce the rate of heat loss, Golden-crowned Kinglets will huddle together at night on the tips of exposed conifer branches. Some of the heat lost by each bird is absorbed by a neighbor.

The two species of kinglets differ in their vocalizations. Golden-crowned Kinglets have a very high-pitched tsee contact call throughout the year. This note is one of the first to go for birders experiencing some hearing loss as they age. The song is a series of thin, high-pitched ascending notes.

Ruby-crowned Kinglets are much easier to detect by ear. Their contact call can be described as che-dit and is often given in a series. It’s easy to pick up and highly distinctive. The song is a complex series of galloping notes and trills that are surprisingly loud for such a small bird. The song is audible for over half a mile in open habitat.

Visit the AllAboutBirds website to hear recordings of the vocalizations of both species. Use the search function to find each species and scroll down to the vocalizations section.