A “superflight” irruption for North Carolina – the pine siskins

As mentioned in my previous blog, North Carolina’s Piedmont region is experiencing a spectacular winter irruption of multiple finch species. So many birds have migrated south from the northern USA and Canada that scientists are calling this a “superflight” year. The first to arrive in my yard during this irruption were the pine siskins (Spinus pinus).

Scientists don’t yet know as much about siskin migration as they would like to know. From 1960 to 2011, almost 675,000 siskins were banded but only 2000 of them were ever spotted again.

However, it is known that the siskins enjoy eating many types of seeds. The finches’ usual diets up North center around the fruit and seeds of spruce, pine, hemlocks, maples, and beech trees, among others. Some species favor certain trees, while others enjoy eating a large variety of seeds.

In “mast years,” the forests provide large amounts of seeds that both feed animals (e.g., birds, squirrels) and provide the germination material for new vegetation. In other years, the forests produce very few crops because of fires, drought, and outbreaks of spruce budworms that eat the needles of spruce and balsam firs, which can kill the trees. In 2020, it was noteworthy that authorities in Quebec were unable to completely treat the forest trees for budworms because of the COVID epidemic.

 

Some trees also have slow biological cycles. For example, the Eastern white pine (Pinus strobus), known to the Iroquois as the “tree of peace,” has cone production that peaks every 3 to 5 years.

When mast years have taken place and there are large budworm infestations, the finches have plenty to eat and their numbers increase substantially. When the following seed- and cone-poor years occur, the large populations then need to travel further away to find sufficient food supplies and that is what has now brought them to our area.

The pine siskins arrived in my yard in late autumn. They came in a large crowd, with some 30 birds flocking to the feeders at a time. Most of these little brown and beige birds have a trace of yellow on their wings.

About 1% of the siskins – all males – have more yellow or yellow-green coloring on their backs, heads and under-tail coverts. These so-called “green morphs” also have less streaking on their chests. The siskins above may be in this group. Interestingly, whereas female birds of many species prefer brightly colored males as their mates, female siskins appear to choose males with less yellow to distinguish them.

 

What really distinguishes the siskins for me – in addition to their penchant for visiting in large groups – is their feistiness. They seem to be very troubled by the idea that there may not be enough seeds to satisfy their appetites if many other birds are around.

Below you see them challenging a house finch, a downy woodpecker and cardinals.

 

And this includes not only birds of other species but also their species mates with whom they arrive! They first will open their seed-filled mouths to “yell” at the incoming diners.

Next, they may open their wings in a challenging display.

 

Sometimes they seem to be taking food from another’s mouths! (But perhaps this is not aggressive but a sign of care between family members?)

Finally, they will fly at their food rivals in an effort to drive them off.

Unlike other members of the finch family, the siskins not only eat a very large variety of seeds from conifers, deciduous trees, grasses, weeds and flowers. They also forage for insects and have been seen to drink from sapsucker sapwells in trees.

A group of siskins can clean out a feeder with mixed seeds in my yard in very short order indeed. They have developed body mechanisms to help them survive cold nights: increasing their metabolic rates and gaining body fat for the winter.

 

This is accomplished by eating more seeds than they can process right away; they can store seeds weighing up to 10% of their body mass in their crop (part of the esophagus) for a short period so that they have access to more energy during the night!

 

Some local birders who were delighted to see them at the beginning of the season are now occasionally voicing “regrets” since large groups continue to visit their feeders. They could refrain from putting out seed and hope the flocks move away so they don’t spend so much on bird seed, but many birders would then miss seeing the other species and don’t want to forego that pleasure.

 

 

Fortunately, the siskins have been eating seeds from crepe myrtles and other trees in my yard so their visits to my feeders have been somewhat sporadic when the weather is mild. When it rains or gets very cold, they return in feisty groups!

“My” yard siskins have also refrained from pecking at the cement of my brick house. Other birders have seen them chipping away at chimney and brick cement – they do this get at minerals contained in the cement.

 

While the siskins migrate in very large groups (e.g., flocks numbering up to a few thousand individuals!), they are still considered to be a common bird that is showing a steep decline in numbers. They are vulnerable to predators as well as contagious diseases spread at feeders such as salmonella.

Although we are still in the throes of winter in North Carolina, spring is fast approaching and it’s uncertain how long these irruption birds will stay. I’ll miss these lively little visitors when travel back up North!

A gathering of gorgeous grosbeaks

If you know birders, you’ve undoubtedly heard that this 2020-21 winter season marks an “irruption” year – a period when large numbers of certain bird species migrate to places where they’re usually not seen. This year is especially notable because it is one of the largest mass migrations that has taken place in about 25 years.

The scientists who study irruptions are calling this season a “superflight,” because all the species in the finch family that breed in the boreal forests of the northern USA and Canada have been moving south. Here in the Piedmont, we’ve been lucky to see several of these species.

The finches that have drawn the most attention from local birders are the evening grosbeaks (Coccothraustes vespertinus) with their eye-catching colors and plumage. They tend to move about in flocks and when they land at feeders, they appear more than willing to share with other birds, like a red-bellied woodpecker (above) or pine siskins (below).

When they land on a feeder, however, they may crowd out others due to their size.

While the evening grosbeaks don’t seem quarrelsome like some other birds, they may still have territorial defense encounters when they are vying for food. Perhaps that is what happened to this female with what appears to be a slight injury below her eye. It is unlikely that it would have come from escaping another type of assault as it has been reported that they have no known predators!

The females are subtly colored in shades of gray-beige with touches of green and yellow on their flanks, neck and near their throat. Their wings are marked with black and white patches.

 

Their coloring may look a bit different depending on the quality of the light and how overcast the day is.

The males are eye-catching due to their vibrant yellow and black plumage, featuring a notable dark yellow stripe over the eyes and a bright white patch on black wings.

Both females and males have the very thick, conical bills characteristic of their species.

Watching them at breeding time would be interesting as it does not involve song but instead features the males dancing for their prospective mates.

In the summer, the evening grosbeaks eat insects, including the spruce budworm, which is a tiny caterpillar. Their winter diet includes large seeds, berries and tree buds; maple samaras (papery winged seeds) and sunflower seeds are favorites (especially the gray-striped kind).

In 2018, a few individual evening grosbeaks were spotted in the Triangle but not many people had the chance to see them. I was fortunate to have three visit my feeders for an afternoon when it was snowy.

This year, none have visited me, but they have been very present in our area, especially at the feeders of bird enthusiasts Bert Fisher and Leto Copeley. This lovely couple welcomed birders to visit their yard by appointment (with limited numbers of visitors wearing masks in the large area).

 

Bert kindly updated everyone on the birds’ comings and goings. Their number increased over time to a high count of over 60 birds seen at one time. They often sit high in the trees of the wooded property and then suddenly descend to sit in groups on platform feeders and to pick up fallen seed on the ground.

Over time, the evening grosbeaks have expanded their “territory” over the Northeastern USA, partly in response to increased planting of boxelders (Acer negundo, a type of maple) as shade trees. The seeds of the box elder are available throughout the winter and are a preferred food for these large finches.

Like numerous other bird species, evening grosbeak populations have declined steeply over time. Between 1966 and 2015, their numbers on the East Coast declined by 97%. Continued logging of forests in northern North America, avian diseases, aerial spraying of insects and climate change may all contribute to further reductions of this group of birds.

Researchers are now collaborating in an Evening Grosbeak Project that aims to compare flight calls, genetics and breeding behaviors of five distinctive sub-groups in this species. They are distinguished by the types of calls that they make and birders are asked to help out by submitting recordings to the eBird website.

It appears that Type 3 (Coccothraustes vespertinus vespertinus, the most irruptive of all five sub-groups) is the call type which has traveled to our area. It has a call that is similar to that of a house sparrow.

Some northeastern grosbeaks are now being tracked by the Project. An avian ecologist with the Pennsylvania Natural Heritage Program recently was able to band 47 birds so that sightings of them elsewhere can be reported. He also put a new model of solar radio tracking tags on 29 of the birds, which can help monitor their movements throughout their lifetime.

Evening grosbeaks can live well into their teens; the oldest banded individual was found when he was 16 years and 3 months. Perhaps some of those visiting us this year have been here before during food-poor periods up North. It will be interesting to see when they next decide to visit our area in the future and hopefully a few will visit me.

 

I’ve added some of the trees that tend to attract them, such as winterberries, maples and crabapples, to complement the junipers, pines and elms in my yard, so the welcome mat will be out!

Chilly mornings and nights – birds coping with and resisting the cold!

Many birders focus their attention on nest boxes in the spring and summer, hoping to see avian parents bringing food to nestlings – and if they’re lucky, getting to see the young fledge. Those blessed with yards or a voice in deciding what goes in public spaces may create more such places by putting up nest boxes on poles and trees. (Poles with baffles are a better choice as it makes it harder for snakes and raccoons to enter and eat the eggs and nestlings.)

What many people don’t always realize is that nest boxes can be enjoyable birding spots in the fall and winter, too. As more and more people choose not to leave snags in their neighborhoods and/or have trees removed from properties, birds are losing places to construct their natural nest cavities. Nest boxes help make up a little bit for that habitat destruction.

 

In the winter, birds check out nest boxes to get a head start on choosing possible nesting sites come spring and summer. In my own yard, especially the Eastern bluebirds (Sialia sialis) and brown-headed nuthatches (Sitta pusilla) will visit one nest box after another to decide which one they might choose as a brooding site in the spring. The nuthatches may be accompanied by a youngster from the past summer who will help raise their new siblings.

 

 

Various species of birds also use nest boxes as warm overnight abodes when the temperatures fall to near freezing and below. Besides the Eastern bluebirds and brown-headed nuthatches, I’ve seen white-breasted nuthatches, Carolina wrens (Thryothorus ludovicianus) and downy woodpeckers (Picoides pubescens) checking out a nest box inside and out.

    

Carolina wren                                                 Downy woodpecker

Some species even use a nest box as a communal overnight refuge, with 12 or more birds squeezing together to conserve their body heat. I haven’t seen so many birds enter a box but perhaps I’m not looking at the right time.

The competition for nest boxes as warm overnight roosting spots can also be intense. A male downy woodpecker in my yard has adopted one particular box as his overnight abode, but the bluebirds would rather have the refuge for themselves. He gets there in the late afternoon and sometimes must pass angry birds to squeeze through the hole.

The bluebirds will then scold from atop the box and while hovering in front of the entrance, but he hunkers down and refuses to leave.

It’s interesting to see that the nest boxes also serve other creatures. Various birds perch on nest boxes while checking out the yard to see what’s going on, like this beautiful Northern flicker (Colaptes auratus).

One day, when looking out my window, I was certain I had seen a lizard peeking out of a box hole. Shortly thereafter, when I was outside, I caught a glimpse of a head and went over to open the box. And it turned out that a Carolina anole (Anolis carolinensis) is sometimes using that box as a place to rest! The birds don’t enter when s/he is there as far as I can tell.

When it’s cold and damp, you can also see birds using other measures to stay warm and resist the cold. Most birds eat quite a lot to put on body fat that is used up at night through shivering (which helps keep them warm). This means you may have crowds at bird feeders with species sharing space as they increase their body mass.

You may also occasionally get an “invasion” of one species, like the pine siskins (Spinus pinus).

Puffing up their feathers is another strategy that our avian friends use – they trap pockets of warmer air around their bodies.

Ruby-crowned kinglet (Regulus calendula)

                                              Brown thrasher (Toxostoma rufum)

           

Chipping sparrow (Spizella passerina)         Dark-eyed junco (Junco hyemalis)

The birds keep their feathers in good condition by engaging in vigorous preening. Some water birds oil their feathers to waterproof them, while others grow special feathers that disintegrate, producing a special waterproofing powder. And birds like mallard ducks (Anas platyrhynchos) have a special blood circulatory system in their legs whereby they lose only about 5% of their body heat through their bare feet.

Creating wood piles and leaving dried leaves and stalks from summer and fall grasses and shrubs can provide birds with some shelter from winter winds and cold, so my yard is now home to five wood piles. Several species of birds also seek out protected roosting areas when the deciduous trees and shrubs lose their leaves and the branches no longer provide hiding spots from predators. My native holly bushes serve that purpose for the lovely white-throated sparrows (Zonotrichia albicollis), as well as Eastern towhees (Pipilo erythrophthalmus) and Northern cardinals (Cardinalis cardinalis). I’m glad it keeps them returning to the yard!

As 2021 gets underway, I wish you readers all the best – hope this new year is healthy, happy and as worry-free as possible for you! And thanks for reading my blog. 😊

Serendipity in a stressful year

2020 has turned out to be quite a stress-filled series of months on multiple fronts, so unexpected pleasures and delights are very welcome. For birders in North Carolina (NC), that scenario has luckily been playing itself out this fall and winter. Several unexpected and unusual birds have been spotted in our state, including a Kirtland’s warbler, vermilion flycatcher, MacGillivray’s warbler, and sandhill cranes.

Many bird lovers have traveled to catch sight of these surprising visitors. While I’ve mostly avoided groups the past nine months as part of my COVID-avoiding measures, last week I did join the human migration to an NC home about 20 miles away to see a bird that is normally only found in the northwestern United States – a varied thrush (Ixoreus naevius).

The opportunity to see this lovely bird was offered to the local community by homeowners Tony Hewitt and Marla Wolf. They generously allowed people to come to their suburban yard (by appointment) to watch over the backyard fence to catch sight of the thrush.

When I visited on a “slow” day, it was easy to socially distance oneself from other birders and photographers. Only a couple other people were there for a while (and I was alone some of the time) waiting for the thrush to make an appearance. Everyone wore masks, some having double masked as well.

The varied thrushes normally migrate back and forth in the area stretching from Alaska, through Canada, down to northern California, as shown by this map from the Cornell Lab of Ornithology. The website remarks that a few of these birds occasionally wander outside their normal range to the Midwest and Northeast. Seeing one in the southeastern USA is highly unusual.

Map credit: https://www.allaboutbirds.org/guide/Varied_Thrush/maps-range#

This robin-sized bird is a real stunner – his orange, grey, yellow and white feathers grow in a wonderful pattern. The colors seem to vary a bit, depending on the quality of the light falling on them and the background against which you see him. But he is handsome from any angle – front, side or back!

Something I found particularly interesting was a pattern of wavy lines in his tail feathers when the light hit them in a certain way. This was not something that I saw mentioned in descriptions of its physical characteristics. The observation made me want to photograph the thrush again to see if this would show up again.

 

It is interesting to note that one varied thrush crossed the Atlantic and turned up in Great Britain in 1982. It was a unique bird since it represented a rare variant of the species in which the orange feather coloration has become all white. Only five such representatives of this mutation have been recorded since 1921.

In its home range, the varied thrush prefers to stay in dense, coniferous forests near water. The NC visitor is taking advantage of a backyard nook that Marla designed with multiple shrubs and some open space.

The home is not far from a lake, but the thrush is taking advantage of a bird bath for drinks, which Marla kindly had moved so that it was better visible for visiting birders looking over the fence.

Varied thrushes usually feed on insects, foraging on the ground and often under dense cover.

The thrush’s insectivorous diet can be wide-ranging and include ants, beetles, caterpillars, crickets, earthworms, millipedes, snails and spiders.

  

They also eat berries, either in trees or on the ground, during the autumn and winter months. 

Our NC celebrity bird is obviously enjoying seeds furnished daily by Tony and Marla.

A notice placed by Tony near fence announced that the thrush seemed to come out in the open every 30 minutes or so. It turned out that this was indeed the case the first hour that I was there; then the bird came after a couple 15-minute intervals.

He certainly seemed to be a creature of habit because I noticed that after eating, he would go back into the dense undergrowth for several minutes and then re-emerge to take a couple drinks at the bird bath. Eating obviously was making him thirsty and noticing this habit meant it was possible to get “camera-ready” for another appearance.

When it is breeding time, male varied thrushes begin to establish territories and confront other males with threat displays. These begin with the bird cocking his tail and turning it towards his rival, while he lowers his wings. If the rival bird does not go away, the thrush will lower his head, raise and fan his tail and then spread his wings out to the side.

Obviously, our NC bird had no rivals around but there were many other birds foraging in the ground underneath the feeders. They included Northern cardinals, white-throated sparrows, pine siskins and downy woodpeckers among others. And it seemed that “our” thrush was sometimes warning them off.

Or perhaps he was just flashing his wings to scare up insects hiding in the fallen leaves.

There are still large numbers of varied thrushes, with an estimate of some 20 million in the current global breeding population. However, the North American Breeding Bird Survey recorded a cumulative decline of the species of 73% between 1966 and 2015. Logging, wildfires and forest fragmentation are ongoing threats to their breeding habitat.

This is only the fifth time that a varied thrush has been seen in North Carolina. The first sighting was in 2005; three other birds were seen in 2010. No one has any idea what got this year’s bird so far off-course during its migration and no one knows how long it will stay around.

Tony and Marla have kept a visitors’ book (with hand sanitizer available for signers) and many people have been recording their visit. When I visited, more than 110 people had already come by, including some birders from Virginia and Tennessee. More people have since stopped by the Hewitt-Wolf residence to admire this vagrant bird. We are grateful to them for giving us this opportunity!

It’s apparent that the serendipitous sojourn of this gorgeous bird has been a welcome gift to many people – both those who saw it in person and those who’ve admired photos distributed through facebook groups. We hope the bird will survive the winter here and be able to return to its home grounds out West so that its journey has a happy ending!

 

Life on late winter-early spring farmlands

Although it’s taken me some time to process photos taken earlier this year, I’d still like to share what I was seeing in late winter and early spring when stopping at farm fields. These sometimes muddy and stubble-covered parcels of land can offer wildlife watchers nice views of birds and occasionally other animals, unobstructed by a lot of foliage. So visits to roadside farms and ponds were on my early 2019 nature-walk itineraries.

Farm fields are often bordered by stands of trees where animals can retreat if they become disturbed by humans standing around aiming long camera lenses at them. The white-tailed deer (Odocoileus virginianus) above were browsing one morning and seemed unconcerned as I photographed nearby birds. When I turned to watch them specifically though, they decided to move back into the woods bordering the field.

Many farmers put out bird boxes on fences bordering their fields; in early March, the Eastern bluebirds (Sialia sialis) were already checking out and starting to furnish potential nest sites. Here a male was flying away from a nest box while his mate was gathering pine needles.

The fences offer other birds a good vantage point for observation, too. A Northern flicker (Colaptes auratus) perched on a fence post to look around and then flew to a branch high above me.

 

A bird present in large numbers was the brown-headed cowbird (Molothrus ater). One morning, a friend and I counted some 200 birds in one small group of trees. Many people think they are an invasive species and dislike these birds intensely because they evolved a behavior that can endanger other birds. The cowbirds, who are native to America, were originally present in prairies where they followed the buffalo. This meant they did not stay in one place long enough to tend a nest, so they began laying their eggs in other birds’ nests. The young cowbirds hatch first and then may throw out the other eggs or hatchlings or they eat so ravenously that the other nest mates don’t get enough.

It certainly is disconcerting to see a small warbler feeding a large cowbird fledgling and a couple bird species have been endangered by the behavior. But I don’t dislike the cowbird because of this – they did not choose how to evolve and the behavior developed as an adaptation, not an “evil” practice. They are attractive birds. And the sounds they make are lovely, akin to water droplets falling into a pool.

 

The American robins (Turdus migratorius) were also present in abundance; they tend to flock together in the winter and early spring. One farm had a boggy area with some cyprus trees and the robins were busy looking for insects among the cyprus “knees” (Taxodium distichum). These woody structures that grow out of the roots may help stabilize the trees when they are standing in water but scientists have not yet definitively identified their purpose.

There were other trees near the cypresses; in one, the cocoon of a Polyphemus moth (Antheraea polyphemus) was hanging high overhead. It also pays to look around to see who is flying u[ ahigh above those trees and fields. It’s not uncommon to see Canada geese (Branta canadensis) flying from one farm pond to another.

Red-tailed hawks (Buteo jamaicensis) soared over different fields I visited.

Red-shouldered hawks (Buteo lineatus) also made an appearance.

And one of my favorite raptors often eluded my efforts to capture a portrait. Only a couple times was I able to catch a beautiful kestrel (Falco sparverius) speeding by in flight.

The robins were feeding in the fields as were several other bird species.

 

Yellow-rumped warbler (Setophaga coronata)

Savannah sparrow (Passerculus sandwichensis)

Pine warbler (Setophaga pinus)

A pair of Northern mockingbirds (Mimus polyglottos) was taking advantage of numerous cow patties left behind on one farm field in their search for insects. They were flashing their wings repeatedly; I’m convinced that this was behavior designed to scare up bugs so they can catch them easily.

 

 

Other birds were following them around in the field, apparently taking advantage of the insect smorgasbord. Two of them were a song sparrow (Melospiza melodia) and a field sparrow (Spizella pusilla).

This year, it was also my good fortune to see a bird new to me in one farm field, the lovely horned lark (Eremophila alpestris). Although these birds are not considered endangered, their numbers declined by 71% between 1966 and 2015.

I couldn’t get close to the larks but one day I did catch a bird taking a dust bath in a gravel and dirt road next to their preferred field. On a second visit to that farm, I again saw a lark in the road and then another lark joined it.

It turns out that female larks perform a courting display that looks very similar to actually taking a dust bath, so I got to see a mating behavior that I hadn’t expected!

Reading about the behavior, I discovered that if male larks see a female who is dust bathing, he may mistake what she’s doing and try to mate with her when she’s not ready.

So reproductive life is a bit difficult for those males, who look so adorable when they raise those head feathers to project two little black horns.I will leave you here with a few more views of a horned lark who was singing and foraging not too very far from the road.