Life in Maine was pretty good for Bobolinks in the 1700 and 1800’s. Much of southern Maine had been converted to farmlands. They hay fields that farmers maintained to feed their livestock were just the ticket for this grassland bird.

But since the turn of the 20^th century, many farms in Maine have reverted to forest. I am sure you have encountered the remnants of stone or wire fences as you walk through a patch of forest now. Over 90% of Maine is now forested, the highest percentage of any state. That statement includes sparsely populated Alaska because much of northern Alaska is treeless tundra.

Natural grasslands in Maine have always been fairly limited in extent. The Kennebunk Plains, maintained by The Nature Conservancy, is the best known of our remaining tracts of native grassland.

These grasslands are home to a suite of species including upland sandpiper, Grasshopper Sparrow, Savannah Sparrow, Vesper Sparrow and Bobolink. Unfortunately, all these species are in serious decline. These declines are not occurring only in Maine. The State of the Birds 2022 project found that ten of the 15 grassland birds across North America are showing significant declines. Five of these species are classified as Tipping Point species. Since 1970, these species are showing accelerated population declines. In other words, the rate of decline is becoming higher every year. That pattern is a recipe for extinction, hence the notion that these birds are at a tipping point.

The State of the Birds 2022 researchers found that grassland birds have collectively decline by 34% since 1970, the most severe decrease of any other group of birds. Other groups in trouble are shorebirds with a 33% decline, sea ducks with a 30% decline and eastern forest birds with a 27% decline over the same time period. We have good news for waterbirds (18% increase) and ducks (34% increase).

The reasons for the declines of grassland birds are manifold. Over 60% of native grasslands in the country have been lost over the years to agricultural development and the encroachment of abutting forests. Native grasslands close to agricultural fields can be affected by pesticide application on the farms.

Hay fields provide alternative nesting habitat for grassland birds. Alas, there is a tension between farmers and birders because farmers need to cut their fields during the bird nesting season.

Farmers need to cut their hay when the grasses are at their highest nutritive value. In Maine, that critical date is around the end of June into early July. Unfortunately, grassland birds nesting in these fields may not have finished nesting by then.

In an ideal world, farmers would wait until at least July 15 to cut their fields. However, farmers maintain their high fields to maximize the production of high-quality hay, and, in my view, it is not fair to farmers to go beyond simply politely asking them to delay haying. If the farmer refuses, so be it. After all, we all depend on the milk and beef from cows and the wool from sheep that benefit from a productive hay harvest.

I fully support the work of Ag Allies (https://www.somersetswcd.org/ag-allies) in Maine, who pay farmers to delay their harvest but many farmers are reluctant to except cash in exchange for an inferior hay crop.

There is one recommendation we can make to farmers as they cut their fields: cut from the inside out. By cutting from the outside in, the way most of us mow our lawns, nestling and recently fledged birds are herded to the center of the field. As the last of the field is cut, the birds are caught in the center of the field and are easy pickings for predators. Cutting from the inside out, pushes the birds toward adjacent forest or shrubs, reducing predation risk.

A more effective way to try to stem the decline of grassland birds is to acquire tracts of open land like abandoned fields and brushy areas and manage them for grass growth. Such grasslands will likely need to be mowed or burned periodically to prevent succession of the field to forest. Without the need to produce high-quality hay, the mowing or burning can be done well past the nesting season.

Throughout the history of life on our planet, the human species is certainly the one that has posed the greatest threat to other forms of life. The various ways we have altered our environment has been profound in the last 200 years.

In the year 1000, the human population was around 275,000,000. The population hit a billion in 1800 and now exceeds eight billion people. Our population has resulted in great losses in natural habitat. We need to look beyond on our own self-interest and conserve other species. But what are we to do?

One of the simplest actions we can take is to protect existing habitat. Contributing to land trusts and non-governmental organizations as well as maintaining our own property are all helpful. This habitat-based mechanism of conservation considers the communities of organisms collectively. It’s the rising tide raises all boats idea.

However, some species are declining while others are increasing, many due to the direct or indirect effects of human activities. To help those species, we need conservation actions targeted at improving the lot of the declining species. Such actions entail practical and ethical problems.

Consider the Mute Swan, an invasive species from Europe. With their sinuous necks and large size, these swans are appealing birds. However, they pose significant threats to co-existing native waterfowl by competing for food and destroying aquatic plants. They are aggressive birds and will attack humans. The approach of many wildlife agencies is to kill these invasive birds because of their effect on native birds. That decision seems reasonable to me.

The European Starling was introduced into North America in the latter part of the 19^th century. They have since spread throughout North America with a population of over 200 million. Starlings have a number of impacts including competing with native cavity-nesting birds for nest holes, spreading the seeds of invasive plants and eating and reducing fruit quality of apples, grapes, cherries, strawberries, and peaches.  I have little doubt that had starlings been introduced in the past decade, wildlife biologists would have quickly removed them.

The Kirtland’s Warbler, mostly restricted to the jack pine forests in northern Michigan, fell to a population of only 174 males in 1974. Restoration of the species was begun with the use of fire to create more suitable jack pine forests and intensive trapping of Brown-headed Cowbirds. Cowbird females lay eggs in the nests of other species, fooling the parents into raising cowbirds. Cowbird parasitism on the nests of Kirtland warbler’s was 59%.

Cowbird removal was successful, and Kirtland’s Warbler is recovering and spreading their range. But Brown-headed Cowbirds are native species. The species historically followed bison around in the west but the clearing of land in the east for agriculture created habitat for them to expand their range. Cowbirds only arrived in the Kirtland’s Warbler range around 1880.

What is the ethical perspective on this conservation practice? Cowbirds were only in Michigan because of human activities. Do we choose the warbler over the cowbird? Should we have let nature take its course? Should the prevention of an extinction win the day?

The Northern Spotted Owl is a resident of old growth forest in the Pacific Northwest. Their habitat is shrinking due to logging. The closely related Barred Owl has been expanding westward, aided by human alterations to the habitat. Barred Owls outcompete Spotted Owls. The U.S. Fish and Wildlife Service recently submitted a proposal to kill 470,000 Barred Owls over the next 30 years to prevent Spotted Owl extinction. In addition to practical problems in a project this size, the project also has significant ethical implications.

 A recent article in Conservation Biology reviews the practice of killing gulls on offshore islands in the Gulf of Maine to protect nesting terns, whose eggs and chicks are subject to gull predation. The argument has been that gulls have increased unnaturally over the past century in the Gulf of Maine because of human impacts. The argument then is that terns are doing poorly because of the increased gull numbers.

The authors dispute the narrative that gulls are overpopulated in the Gulf of Maine. They argue that gull removal is based on precarious reasoning and may be deterring conservationists from finding more effective ways to improve the plight of terns.

Today we will consider variability in birds. If you take a good look at birds with streaks on their breasts like Yellow Warblers, Song Sparrows or Pine Siskins, you will notice that within each species the pattern of streaking is a little different among individuals. It doesn’t take a lot of practice to be able to distinguish different Downy Woodpeckers or Hairy Woodpeckers coming to your feeder by the shape of the patches of black, white, and red on their heads. I’ll bet you will be surprised at how many different woodpeckers are visiting your feeder.

If we compare individuals within a species across their range, we often see more striking variability. For instance, our Yellow-rumped warblers have white throats while those west of the Rocky Mountains have yellow throats. Male Dark-eyed Juncos in New England are slate gray above with white undersides. Male Dark-eyed Juncos from the Pacific Northwest have a dark brown head and light brown back while those from the Dakotas have some white in their wings and Rocky Mountain males have pink sides. The different forms do disperse occasionally, and the Pacific form occasionally find their way to Maine.

In most cases, we do not know the reasons why certain forms occur in particular areas. Perhaps, pink sides give Dark-eyed Juncos in the Black Hills a survival advantage or perhaps the variation is just random.

Biologists commonly use comparative techniques to try to understand variation. If a scientist looks at a number of species and all individuals show a particular plumage color or body shape in a habitat, one can begin to draw strong inferences about the value of those variations.

These comparisons have yielded several rules. Bergmann’s Rule says that birds and mammals that live in higher latitudes or higher elevations are generally larger in size than animals from lower altitudes or from temperate and tropical  habitats.

Allen’s Rule looks at the same gradient and predicts that the smaller body appendages like ears, tails, limbs, or bills should be smaller in arctic or montane species.

Both rules can be explained in terms of heat loss. For birds in colder habitats, minimizing heat loss is critical. Larger birds have lower surface to volume ratios and therefore lose heat less rapidly than smaller birds with their high surface/volume shapes. Heat can be lost very rapidly across long appendages. Think about the huge ears of a desert jackrabbit that effectively lose heat to the short ears of arctic rabbits.

Gloger’s Rule involves within-species variation of plumage color. In wetter areas, the plumage tends to be darker. The basis for this pattern seems to be that feather-eating bacteria thrive in humid environments and darker feathers are more resistant to those bacteria.

I read with interest a recent article in the Journal of Biogeography by a team of Italian ornithologists. They were interested in regional variation of the Barn Owl. Although Barn Owls barely sneak into southern Maine, the species is extremely widespread. They occur on all continents except for Antarctica and on many oceanic islands. Their distribution spans 65 degrees north to 55 degrees south. Barn Owls are therefore excellent model organisms for this study.

As one might expect, significant variation occurs across the range. The Italian team used Bergmann’s Rule, Allen’s Rule and Gloger’s Rule to guide their study. They were interested to see if they could detect regional changes in morphology in response to climate change. As the climate warms, one can predict that owls will become darker and smaller with longer body appendages.

The investigators took advantage of the fact that until 1950 or so, ornithology was practiced with a shotgun rather than binoculars. Those specimens were placed in museums. The authors measured museum specimens taken from 1809 until 2018.

Two of the three rules were supported. Barn Owls are becoming smaller in areas subject to climate warming and their ventral plumage is becoming darker in areas where annual precipitation is increasing. However, bill length is becoming shorter in warming areas, contrary to Allen’s Rule.

Nature often surprises us, much to our delight. In a research project, a biologist follows a standard set of steps: observing a pattern in nature, devising a hypothesis to explain that pattern and then devising experiments to try to disprove the hypothesis. During this research, a biologist will often uncover unexpected behavior and effects. The unexpected result I will describe today is amazing.

The bird of interest is the American Woodcock, known widely across the state to non-birders as a timberdoodle. Woodcocks belong to the shorebird family but with their dark mottled plumage and short legs, they are not typical shorebirds. They are forest birds, probing the soil with their long bill in search of their favored prey, earthworms.

Woodcocks have their eyes set well back on the sides of the head. Except for a narrow sector right behind the head, a woodcock can see almost all around itself without moving its head. Most images though are formed by one eye, so woodcocks do not have binocular vision like we do with our forward-facing eyes. In other words, woodcocks are not able to gauge distances very well. But once a potential predator is detected, the woodcock stands stock-still and its dark plumage blends with the forest floor. A few black stripes on the head break up the outline of the bird so it is superbly camouflaged.

American Woodcocks have an unusual mating system. About 95% of all species of birds have a monogamous mating system. A male and a female will develop a pair-bond and will raise one or more clutches of eggs together.

Some birds like swans, Sandhill Cres and Bald Eagles mate for life with permanent pair-bonds. Others like ducks change partners every year but maintain a single pair-bond each year. Some species with multiple clutches in a season, like the Eastern Phoebe, may change partners with every clutch.

Another type of mating systems involving pair bonds is polygyny where a male maintains pair-bonds with multiple females. The Red-winged Blackbird is a good example.

The tables are turned in polyandry where a female has multiple pair-bonds with males. Phalaropes are polyandrous. Even rarer are polygamous systems where both males and females have multiple partners in the same breeding season.

Woodcocks fit into a fifth category. They don’t believe in pair-bonds. A male tries to attract females. If successful, the male mates with the female and his contribution to any offspring is done. He is back on site trying to attract another female. This type of breeding is called promiscuity. The Ruffed Grouse is another local example. Males drum by rapidly flapping their wings from a stump to woo females.

The mating behavior of timberdoodles is well known. Mostly displays occur shortly before dawn and shortly after dusk.

A male will walk from the forest into a field or other cleared area and begin giving a distinctive peent sound. Then it explodes into the air, flying as high as 150 feet and then slowly descending in circles, chirping the whole while. Air moving through their curved primary feathers cause a whirring noise. The male lands at its original spot. A female won by his behavior may approach, mate and then leave him for good.

So, here is the remarkable new knowledge. A team of 28 researchers put satellite transmitters on more than 300 woodcocks to track their migration. Woodcocks overwinter in the southeastern United States and breed from the mid-Atlantic states into Canada as far west as Manitoba.

Of 200 tagged female woodcocks, over 80% nested along their migration route and then continued northward. Some females nested as many as six times during their migration. Because young woodcock can fend for themselves soon after hatching, a female can abandon her chicks soon after hatching and continue her migration.

We are used to thinking of birds in the spring migrating to the breeding grounds and then nesting. Woodcocks have muddied the water, nesting while migrating. This unexpected result would never have been elucidated without the help of the satellite transmitters.

Earth Day, is one of my favorite days of the year. Established in 1970 by the leadership of peace activist John McConnell and Gaylord Nelson, a Senator from Wisconsin, Earth Day is a time for all us to renew our efforts to take care of Mother Earth and all the many species that share this planet with us. At least for those of us in the Northern Hemisphere, Earth Day is well timed, occurring at the peak of spring with the promise of rebirth and renewal as plants leaf out and flower and animals return or emerge from hibernation.

Earth Day was established in the nascent days of the environmental movement. This movement was perhaps given the greatest boost by Maine’s own Rachel Carson whose 1962 book, Silent Spring, documented the devastating effect of the use of DDT on many birds.

There is no shortage of ways we can help improve the health of the earth and all of its organisms. Some ways are recycling, planting native plants in your yard, turning down the thermostat in your house a few degrees, and paying voluntary carbon offsets for your air and car travel.

Of all the insults we humans have visited on our planet, I think the emission of greenhouse gases has caused the most terrifying effects. There is no doubt that air temperatures have consistently increased over the past 100 years with no sign of slowing. Ocean temperatures are setting new high records every day!

Some denialists argue that the earth has seen great variation in temperatures over geological history and that current climate warming poses no problems. That assertion that the earth’s temperature has varied greatly is absolutely true but the rate at which global temperatures are changing is unprecedented.

Temperature has a fundamental effect on all organisms. As temperatures rise, organisms must find more optimal temperatures by moving poleward or upward on mountains. For organisms with limited mobility, perishing is the likely outcome.

Warm tropical ocean temperatures are causing widespread coral reef mortality. We expect these corals to move poleward via dispersal of their larvae to find ocean waters below lethal temperatures.

The U.S. Forest Service has released models of the distribution of trees in the northeast in the year 2100 assuming that carbon emissions continue at the same rate. Sugar maples and balsam fir will no longer be able to live in Maine. Nesting birds that depend on balsam fir forests like Swainson’s Thrush, Winter Wren and Red-breasted Nuthatch will become much less common.

Some may say, organisms can simply move toward the poles or to higher altitude to persist. The problem is that some organisms will run out of space. Polar bears depend on pack ice to forage for seals. With global warming, polar bears cannot move northward from their arctic habitat. They are in real trouble!

The science of phenology concerns the timing of biological events. Leaf-out of red maples, first flowering of white elderberry, the first arrival of Yellow Warblers in the spring, first egg-laying of Ovenbirds, the emergence of groundhogs from their hibernation burrows, the first calling of spring peepers, and the emergence or caterpillars from hibernation  are all examples.

With global warming, we expect phenological events to occur earlier. We have abundant evidence of that happening already for many plants, insects, birds, amphibians and mammals.

An insidious effect is a phenomenon called phenological disconnect. When two or more species that depend on each other fall out of sync, disaster can occur.

The Pied Flycatcher is a common Eurasian bird that winters primarily in Africa. They feed their young seasonally abundant caterpillars that feed on oak leaves. In Europe, oak trees are leafing out about two weeks earlier and the caterpillars are right with them. However, the flycatchers are on their old schedule and are arriving after the caterpillar peak has passed, leading to starvation or slower development of their chicks.

What can we do to prevent such tragedies? Earth Day should inspire us all to do all we can every day to reduce the carbon emissions that are heating our planet.

The invasion has begun. Around March 20, flocks of bohemian waxwings appeared in Maine. What a joy it was to have a flock of 100 in our yard. We are hardly alone; flocks are present across the state.

We have two waxwings in Maine: the Cedar Waxwing that nests here and the Bohemian that is a winter and spring vagrant. Sometimes, Cedar Waxwings overwinter so we can be blessed with both species of waxwings on a winter’s day. The two species often comingle in a single flock.

Bohemian Waxwings belong to a group of birds called irruptive species. These are birds that occur to our north but may in some years be forced south into Maine or further south in search of food.

The best-known irruptive species are finches like Common Redpoll, Pine Siskin, Evening Grosbeak, Pine Grosbeak, Red Crossbill, and White-winged Crossbill. The seed availability for these birds must have been pretty good to our north because Maine had very few of these irruptive birds this winter except for a moderate flight of Red Crossbills.

Red-breasted Nuthatches are also an irruptive species. We do have a breeding population in Maine, but their numbers are greatly increased in some winters by vagrants from the north.

Snowy Owls, Great Gray Owls and Northern Hawk Owls are yet more irruptive species. Their irruptions are not very frequent and involve relatively few birds.

Finally, aptly named Bohemian Waxwings clearly are irruptive species. In some years, they invade in November and December and are well represented on our Christmas Bird Counts. Even when they fail to appear in the winter, we can usually count on an influx of birds in March, with some persisting into early May.

Bohemian Waxwings nest in northwestern Canada into Alaska. Like Cedar Waxwings, Bohemians are fruit-eaters. We know that fruit production by winterberries, crab apples and other fruit trees varies widely from year to year.

After the nesting season, Bohemian Waxwings form flocks that wander in search of fruits. The fruits can be depleted quickly so the flock must keep on the move. They move southeastward, ultimately arriving in northeastern North America, including northern New England.

To find Bohemian Waxwings, check out areas with large plantings of ornamental fruit trees. The Colby College campus and the UMO campus are particularly good although any fruit tree with hanging fruit will attract these waxwings.

In his Birds of Maine, published in 1908, Ora Knight reported that Bohemian Waxwings had not occurred in Maine for years. This observation was echoed by Ralph Palmer in his 1949 book, Maine Birds.  These waxwings staged invasions of Maine every two or three years in the 1970’s. Since then, they can almost be considered an annual vagrant. We do not have a good handle on why Bohemian Waxwings have increased as winter visitors over the last 120 years. I just consider us lucky to have them around more often.

Waxwings have wonderfully silky, soft plumage. You can appreciate that with a close-up view through your binoculars or spotting scope.

Distinguishing a Bohemian Waxwing from a Cedar Waxwing can be daunting to the uninitiated but is straightforward with a decent look. The two best characters are the cinnamon undertail feathers of a Bohemian. In Cedars, those feathers are white.  The wings of a Bohemian have white patches; a Cedar lacks those patches.

Bohemians are slightly larger and grayer than Cedars. Their buzzy call is pitched slightly lower than Cedars.

Have you ever wondered why waxwings are so named? If you look carefully at the tips of the secondary wing feathers of a waxwing, you can see red deposits. Those structures look a bit like wax but are obtained from the red pigments of fruits the birds eat.

The size and number of the waxy tips increases with age. This feature allows females to choose older males as mates, who generally make better parents.

As birds move from the non-breeding season and nesting season, I enjoy watching the changes in social behavior of the birds. In particular, I look for how birds react to other members of their own species.

Social behaviors are so varied that we will only consider the songbirds, variable enough in their own right. During the nesting season, most songbird males establish and vigorously defend a territory. The only other birds allowed on the territory are its female mates (and any visiting female that is looking to mate).

Territorial social behavior is worthwhile when resources, usually food, are at some intermediate level. If food is scarce, there is no reason to devote energy to defending an area with inadequate food. If food is superabundant, there is enough for everybody and again defending that resource makes no sense. That’s why you can see tons of birds at your birdfeeders that you generously keep stocked.

With moderate food, a songbird pair can find enough food for them and their young but not enough to share. So vigorous defense is the right behavior. The male will defend a territory that is just big enough to provide sufficient food. Keeping other males out is an added benefit of the territory.

Outside the breeding season, flocking behavior frequently occurs. A flock may consist of just a few birds up to thousands. In Africa, the Red-billed Quelea (a sparrow) may occur in flocks of a million birds!

Flocking confers two advantages. A flock of birds has lots of eyes to detect predators. Vigilance against predators increases as flock size increases.

Flocking also increases food acquisition. In nature, the foods that birds prefer often occur in patches. A productive patch of winterberries is just the ticket for American robins and waxwings. An isolated birch tree bears enough seeds to provide a few meals for goldfinches and redpolls. Those patches will be found if there are enough birds looking.

Flocking and territoriality are not incompatible behaviors. During the winter a pair of Black-capped Chickadees will expand their territory from a couple of acres during nesting to 10-25 acres. These resident adults are joined by 8-20 other Black-capped Chickadees. These birds are all juvenile birds and all are unrelated to the resident adults. The residents kick their kids out of the house in the summer only to have other chickadees’ kids descend on them.

These flocks are usually mixed-species flocks as other birds join the merry band, usually just one or two of each species. Common species are Red-breasted and White-breasted Nuthatches, Tufted Titmice, Golden-crowned Kinglets and Downy Woodpeckers.

Yet another social behavior, mate selection, occurs in these flocks. There are usually an equal number of male and female juvenile chickadees in each flock. Over the course of the winter, the young birds form pair-bonds.

In late spring, the flocks break up and the resident male will contract the territory to a smaller territory. The newly formed chickadee pairs will use a couple of acres of the now unoccupied winter territory to begin a family of their own.

You can see evidence of this switch-over at your bird feeders. All during the winter, you may see a dozen or more chickadees at your feeder. These are birds from one winter flock. Within a few weeks, you will see chickadees in ones or twos at your feeder. The winter flock has dissembled.

Our migratory nesting birds show a variety of social behaviors between nesting grounds and wintering grounds. In Jamaica, American Redstarts and Black-throated Blue warblers maintain individual territories. Pairs do not migrate together so it is each bird for itself during the winter.

On the other hand, it is common to see Chestnut-sided Warblers, Common Yellowthroats and Cape May Warblers in mixed-species flocks roaming widely, showing no territorial behavior. One trick to successful tropical birding is to listen for mixed-species flocks and get on them quickly before they move on.

A reader, Tony Scarpelli, wrote recently with some questions about the long migrations many birds undertake. We had an interesting exchange of emails on the topic, and I realized that discussion could make the basis of this post.

Attempts at explaining the reasons for bird migration are challenging. For behaviors that occur so broadly and over thousands of years, we cannot do controlled experiments to nail down the basis of migration. But we can make observations that are helpful in explaining why so many birds migrate.

First, we note that birds and mammals are the only animals that maintain a constant body temperature. So, the resting metabolic rate of a bird or mammal is much higher than in a lizard, salamander or spider whose resting metabolic rate is set by the ambient temperature. Maintaining a high metabolic rate requires large amounts of food.

To understand the physiology of birds, we must recognize that food is everything. If Common Redpolls can find sufficient birch seeds on the edge of the arctic tundra, they can overwinter with temperatures reaching -70 ° F. With enough food, some birds can raise multiple clutches of six or more nestlings in a single breeding season. With sufficient food, Arctic Terns can migrate 36,000 miles in one year.

Thanks to the fact that the earth is tilted on its axis, we have seasons with the northern and southern hemisphere experiencing summer six months apart.

Many of Maine breeding birds are migratory. They come from wintering grounds south of us to take advantage of the long summer days we have. During the summer, equatorial regions have 12 hours of sunlight while we have 17 hours or more. Our longer days allow plants to photosynthesize longer. The plants in turn support insects and other animals that provide bird food. It is easier to find sufficient food in Maine than in the tropics in the summer.

Of course, Maine in the winter is no place to be for these migratory breeders, especially aerial insectivores and leaf-gleaning insectivores. So, moving south in the fall is mandatory. But how far south does a species migrate?

It depends on the availability of the food required. Yellow-rumped Warblers may only migrate to coastal areas of the mid-Atlantic states while many other species migrate to Caribbean islands, Central America, and South America.

Pick any winter day here and compare the day-length to areas further south. Day-length will increase to 11 hours or more in parts of Central America, reaches 12 hours at the equator and continues to increase in the southern hemisphere during their summer. Species like the Bobolink that winter in Argentina essentially experience spring and summer twice a year.

Let’s do a little economic analysis of bird migration. For migration to be worth it, benefits have to exceed costs. Migratory birds incur the huge cost of fueling a migration but the benefit is sufficient food to get through winter.. Temperate resident birds the costs of migration are too high if food is hard to find.

Of the 700 species of birds that regularly occur in North America, 490 of them are migratory. That clearly that shows the costs versus benefits of migration are worth it for most of our breeding birds.

As our climate continues to change rapidly, it is reasonable to think that bird migrations may not be sustainable. We know that migration behaviors can change rapidly. The Blackcap, an Old-World warbler, provides a nice example. This European warbler formerly migrated south to winter in Spain and Morocco. In the 1960’s, some Blackcaps started to migrate to Britain instead. Now, about 10% of Blackcaps choose the new wintering grounds.

All the current migration routes of Maine birds have been used for less than 10,000 years. The last ice-age in Maine started to recede then when Maine was covered with 1.5 miles of ice!

Currently, a dozen bird species are listed on the Maine Endangered Species list. Of these twelve, the Golden Eagle is certainly among the least encountered species on that list.

These magnificent birds, larger than a bald eagle, fortunately are maintaining a stable population globally. They are widely distributed occurring in North America, Europe, Asia, northern Africa, and southern portions of Chile.

In North America, they nest across Canada and Alaska. These birds are migratory breeders, moving south thousands of miles after nesting.

Currently in northeastern North America, Golden Eagles nest in Newfoundland, Labrador, and Ontario.

We can characterize the abundance of Golden Eagles in Maine as rare year-round. Perhaps the best time of year to try to see one is in March in the western mountains when the Labrador and Newfoundland breeders are migrating back to their nesting grounds.

Fall migrants are more common in the western mountains as well, beginning in late September, peaking in late October to November, trailing off in December.

Winter birds occasionally appear but are mostly transient. Sometimes, these eagles are seen in summer, but these birds are also transient. We do know that Golden Eagles once nested in Maine in small numbers. From 1850 to 1950, nesting was reported in Oxford, Piscataquis, Franklin, and Somerset counties at higher elevations. The last successful nesting in Maine was in 1984 and the last attempted but failed nesting was in 1996.

Golden Eagles are efficient predators, taking mammals and birds primarily. Domestic livestock like chickens and lambs are sometimes on the menu, much to the consternation of farmers.

Like Bald Eagles, Golden Eagles will seek out carrion as well. March is a good time to look for goldens where carcasses are available. Five different Golden Eagles were seen in Warren, Maine in one year where carrion was available.

The propensity of Golden Eagles to come to carrion provides a tool for an exciting new program to learn more about Golden Eagles in Maine. Erynn Call, a Wildlife Biologist at the Maine Department of Inland Fisheries and Wildlife, is directing the Maine Golden Eagle Study in collaboration with the Eastern Golden Eagle Working Group and the Conservation Science Global.

The program is a citizen-science project so you can help in several ways. The most important tool of the study is to use trail cameras to monitor food sources. If a Golden Eagle finds and feeds on the carrion put out by reearchers, the trail camera will snap shots of the eagle and we have a solid record of occurrence.

The food put out can be renderings from slaughtered food animals, road kills (with appropriate permits) or legally killed animals.

Obviously, the more trail cameras emplaced across the state, the better our understanding of Golden Eagle distribution will be.

You can volunteer in several capacities. You can monitor and maintain one or more trail cameras. You can make your land available for others to set up a trail camera. You can provide carrion for other volunteers. You can devote time to looking for golden eagles.

To find more information on the Maine Golden Eagle Study, visit: https://shorturl.at/oxBX5

This website has a very useful link with many photos on how to separate Golden Eagles from Bald Eagles. Distinguishing immature birds can be tricky.

Monarch Population Decrease

The first Red-winged Blackbirds, Common Grackles and American Woodcocks are already arriving back in Maine and the spring migration is on.

Of course, birds aren’t the only animals that engage in migration in Maine. Many species of dragonflies and butterflies are migratory. Perhaps the best-known insect migrant is the monarch butterfly.

In the fall, monarchs wend their way southward to northwestern Mexico where they overwinter in massive numbers in high-altitude pine forests.  This year, the monarchs occupied only 2.2 acres of forest compared to a high of 45 acres in 1996. This year’s occupied area is the second lowest on record. A major cause for concern.

In the first half of last November, my wife and I along with four close birding friends participated in a bird tour of northwestern Argentina with Rockjumpers. We flew into Tucuman and worked our way north in a circuitous fashion to our departure city, Salta.

The Andean scenery was spectacular, and the habitat diversity was amazing. Our trips took us from elevations of 600 feet to 15,000 feet and temperatures near freezing to 112 degrees F.

Our trip corresponded to early May in the Northern Hemisphere. However, the rainy season does not begin until around the first of December in Argentina. The dry conditions we encountered meant few flowers were blooming to attract hummingbirds and pollinating insects.

I have birded in Ecuador, Costa Rica, and many Caribbean Islands from November until March. I would frequently encounter North American breeding birds that were wintering in the tropics. Argentina is far enough south that few North American migrants winter there. Nearly every bird we saw was a new one for us.

We quickly learned that Argentina is the land of the ovenbirds (Family Furnariidae). Not to be confused with the Ovenbird we have in Maine, the tropical ovenbirds are closely related to flycatchers. All build permanent domed nests with entrances on the side, just like an oven. Of the 309 bird species we saw, 34 were ovenbirds.

We began our trip with a visit to Reserva Natural La Angostura, a large reservoir. Waterbirds included Coscoroba Swans, Andean Geese, White-cheeked Pintails, Yellow-billed Pintails, Rosy-billed Pochards, Andean Gulls, Gray-hooded Gulls and Cocoi Heron. An embarrassment of riches.

We visited he cloud forest at Rio los Sosa Reserve north of Tucumán the next morning. Highlights were duckling Torrent Ducks in the roaring stream, Red-tailed Comets (a hummingbird with an amazingly long tail), Yellow-striped Brushfinch and delightful Brown-capped Redstarts. Tapaculos are highly secretive ground birds, often heard but seldom seen. I have heard fifteen species vocalize but had only seen a single tapaculo. We were able to get a male White-browed Tapaculo to show by playing its vocalization.

After lunch, we headed north to Rio Tafi. We found a small flock of Andean Tinamous, foraging in a cow pasture. Andean Flickers, Burrowing Owls, and Gray-hooded Parakeets were great to see. A male Tucuman Mountain Finch put on a show for us, posing unobstructed in perfect light.

A morning walk on November 3 at El Divisadero produced a list of 50 species in two hours, including 11 ovenbird species. Highlights for me were Green-barred Woodpecker, Chaco Earthcreeper, Brown-capped Tit-spinetail and Rufous-sided Warbling Finch.

An early morning trip to Cuesta del Obispo was particularly memorable. The cliffs there produced Giant Hummingbird, Andean Condor and a bunch of ovenbirds including Scribble-tailed Canastero, Streak-backed Canastero, Straight-billed Earthcreepers and Cream-winged Cinclodes. Suddenly, our tour guide Dušan Brinkhuizen yelled out “Boulder Finch!”. We were soon all on this gray bird. Dušan had looked unsuccessfully for this species for years in Argentina, Bolivia, and Brazil. Our finch approached within 10 meters of us for some great photo ops.

We visited the Taco Pozo Ponds on the morning of November 6, tallying 88 species in three hours. What a busy place! Waterbirds included White-faced Whistling Duck, Comb Duck, White-tufted Grebe, Great Grebe, Red-fronted Coot, White-winged Coot, Wattled Jacana, and Bare-faced ibis. Overhead, Black-chested Buzzard-eagles and Snail Kites soared. Fork-tailed Flycatchers foraged along the shoreline. As we were leaving, we saw some Greater Rheas in a cow pasture. Amazing birds!

The following day we visited Parque Nacional Calilegua. We saw 35 species of birds there including Variegated Flycatcher, a species I was keen to see. A vagrant Variegated Flycatcher showed up at Biddeford Pool, Biddeford, Maine in November of 1979. It was nice to see this species in its native habitat.

This post covers only a portion of the sites we visited and the species we saw. If you would like to see the complete species list for our trip, site location details and my photographs of 162 of those species, visit: https://ebird.org/tripreport/177054