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!

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!

 

Costa Rican mammals, part 1 – those similar to our Carolina wildlife neighbors!

While the trip I took this past August to Costa Rica was mainly focused on birding, our guides fortunately were also quite willing to stop and look for mammals, amphibians, reptiles and insects – people after my own heart! Here I’ll focus on some of the mammals we saw, starting in this 2-part blog with those that were familiar.

Fellow traveler Nan especially was drawn to the canines we came across – there wasn’t a dog (Canis) that she was unwilling to pet!

 

And they often were very cute.

 

As we drove from one destination to another, it was not uncommon to see light-colored cattle (Bos taurus) grazing in fields. It turns out that about 75% of the country’s cattle are found in Guanacaste province (where we started our trip) and that the Brahman breed is the one commonly raised for the meat industry.

I saw mostly cows, but during a visit to southern Costa Rica last year, we also saw a laid-back steer.

 

There were horses (Equus caballus) grazing in some fields and mountain valleys.

Everywhere we went, there were squirrels scurrying about on the ground, in trees and at feeding stations. The most commonly seen squirrel in the country is the variegated squirrel (Sciurus variegatoides), which varies in color from gray hues to dark brown colors.

  

This species spends most of its time in trees and does not hoard food.

 

Their main dietary selection consists of various seeds, although they also eat acorns, fruit and insects.

   

Another cute rodent is the red-tailed squirrel (Notosciurus granatensis), which is usually found in the cloud forests and wet/humid areas.

Although in some places, people warn against feeding mammals, we saw a red-tailed squirrel enjoying fruit at a restaurant that attracts tourists with its plants that attract hummingbirds.

 

While we do have wild boars in some mountainous North Carolina counties, as well as feral swine in Eastern coastal areas, we will not see collared peccaries (Pecari tajacu) roaming our forests and woods. They share some characteristics of the pig family but are not classified as pigs.

They are both carnivorous and vegetarian, even eating tulip bulbs, which are poisonous for humans. It’s said they usually ignore humans and that was the case for this peccary, which paid us no mind as it plodded about the gardens in one reserve.

 

Our final, at least partly familiar, mammal was observed near the restaurant of a hotel where we stayed. We were lucky to see it since these animals are both arboreal and nocturnal. Fellow birder Ylva got a nice photo of the visiting Central American woolly opossum (Caluromys derbianus). Not only is this marsupial a real cutie, it is also a nectar feeder, pollinator and seed disperser so that we got to see a species that fulfills multiple roles in its rain forest habitat.

Next up – the mammals we won’t see in North or South Carolina (yet).

Growing up barred – Part 1: becoming independent

From the ages of about 8-19 years, I lived in a house that had a nice backyard and was not too far from some neighborhood woods with a creek. As a child, I read under backyard trees, planted a flower garden and played in the woods with friends. While I became familiar with squirrels, robins, frogs and some bugs and loved being outdoors, I didn’t spend lots of time looking for wildlife. And I never saw an owl in the wild.

Now decades later, I’ve had the good fortune to learn a good deal about various members of the wildlife community while spending time finding and watching them. And in the past couple years, I’ve been privileged to see owls up close in the wild; for example, the owl below was perched next to a pathway at dusk when I walked by a few days ago.

This past summer was unique for me, however, because I was able to observe a pair of juvenile barred owls (Strix varia) at the Mason Farm Biological Reserve as they set off on their life’s journey outside the nest. I’d like to share a bit of what I saw with you in a three-part blog. This one is about them finding their independence. The next two will focus on their grooming and interactions.

Barred owl pairs usually bond for life; if one mate dies, the survivor will seek another partner soon after. They tend 2-4 eggs, which hatch after 4 weeks’ brooding and the young leave the nest after four or five weeks. They remain dependent on their parents for food for some time after that even though they may be almost as large as the adults at 16-25 inches in length (40–63 cm); their wing span can stretch up to 3-4 feet (38-49 in, 96–125 cm).

When I first spotted the young owls in June, they could already fly. Nevertheless, they did need to find their balance occasionally as they perched and moved along branches and snags.

 

The owlets were making a keening noise the first time I saw them. At first, I didn’t recognize it, and I thought perhaps some small mammal was in distress.

Eventually, the plaintive call helped me locate them above me in a tree. This particular call apparently is used by the babies to call to their parents. I figured mom or dad was close by as the owlets kept looking upwards and eventually the parents did fly in with a meal – crayfish as far as I could tell.

 

On several occasions over the next 6 weeks or so, I would hear the owlets making that keening call and staring upwards. I figured the parents were nearby, but they were obviously just keeping an eye on their offspring and not feeding them (at least not when I was there).

It was time for the young ones to learn how to get their own meals.  Although barred owls usually hunt at dawn and dusk, the young owls were busy looking for food during the day. The mammals they eat include voles, mice, shrews, squirrels, rats, rabbits, bats, moles, opossums, mink, and weasels. Birds are also a food source and their prey may include woodpeckers, grouse, quails, jays, icterids, doves, pigeons, cardinals, cedar waxwings and grackles. They also eat amphibians, reptiles and insects (e.g., snakes, slugs, lizards, frogs and toads, salamanders, crayfish, turtles, scorpions, beetles, crickets, grasshoppers) and it was the latter group of prey animals that I saw the owlets hunting. Here for example, it appears one young owl had caught a crayfish.

One day, one of the pair was grasping a twig in its beak; I’m not sure what it was doing but it seemed to have some purpose. Perhaps it was testing how strong its beak was.

  

That a strong beak can be an asset became apparent on another occasion. One of the juvenile owls suddenly flew from one tree on the other side of a water ditch to one above my head. There was much rustling of branches and leaves and when I got into a spot where I could see the bird, it became obvious s/he had caught the largest stag beetle I had ever seen at Mason Farm Biological Reserve. It appears that the giant stag beetle (Lucanus elaphus) drinks tree sap, which must have been what it was doing when the owlet got hold of it. The problem for the owl was how to eat the beetle when those large pincers were in the way.

     

The owl would try to grab hold of a pincer but lose its grip; s/he would turn the beetle around but was having a very difficult time getting those defensive appendages off. This went on for quite a long time, which made me feel a bit sorry for the beetle.

 

Finally, the owl had success and was able to settle in for a crunchy meal.

 

They expel the indigestible parts of their prey in owl pellets that they cough up regularly. Here you see the contents of one a friend found under a favorite perching branch at the reserve.

Another day I saw one owlet suddenly fixate on the water ditch.It turned out that quite a large rat snake (Elaphe obsolete; Pantherophis alleghaniensis) was swimming by. The owl watched it carefully as it climbed out of the ditch and eventually crossed the adjacent walking path, never making a move to tackle the reptile. I had remarked on this encounter to the reserve’s land manager, who said it was probably a smart move on the owlet’s part, since the snake was large enough that it could have wrapped around the owl’s head and choked it.

The young owls seemed to have learned a lot about life as a predator as they grew older. It was fascinating watching them explore their world.

Next up: how the owlets cared for themselves.

Gracious and gorgeous grebes nurturing newborns

After birding now for some six or seven years, I’ve come to appreciate all birds since each species can be fascinating to watch. I do have some favorites though that have captured my interest. In 2012, I fell in love with great-crested grebes (Podiceps cristatus), whom I first noticed during a trip to Switzerland. A pair was engaged in their courtship dance, which was simply delightful to see. They circled one another, stretched out their necks, ruffled their feathers and arose on the water facing one another. Their beauty enchanted me, and I felt that I had witnessed something very special.

The rust and black-tinted head plumes and ruff are gorgeous, making these birds very attractive indeed. This led to their being hunted almost to extinction during the 1800s in the United Kingdom because the feathers were desired as decorations or hats. This led to the establishment of the Royal Society for the Protection of Birds in that country and their numbers fortunately rebounded.

Fast forward six years to this past July, and I discovered that these birds are quite common in my land of birth, where I just had not noticed them before. Granted, I was not a birder while living in The Netherlands (I currently live in the USA), but I had managed to take note of house sparrows, mute swans, Eurasian coots and moorhens when walking along canals and ditches. Now, as a much more observant wildlife observer, it was thrilling to see many grebes along the dike bordering the Gouwzee (a body of water bordering Monnickendam that is part of the larger Markermeer nature area). And even better – they were all tending young ones at different stages of development.

The great-crested is Europe’s largest grebe species and the adults are stunning with their reddish-orange head plumes. (They are also found in Australia, New Zealand and African countries.) I discovered that the young look quite different – mostly light in color with black stripes on their heads and pink markings near the eyes.

Their floating nests are often found along reed beds, which were abundant along the dike and a ditch across a road from the dike. A couple mothers had chosen the ditch as their home area and the early morning light made for some nice photos in my opinion as they preened and relaxed.

  

   

The water in the lake on the other side of the dike was less calm but the young ones managed to swim well in the waves; they can already dive shortly after leaving the nest.

Their feet are set back far along their bodies and they cannot walk well. I did not ever see one on land during the week that I was observing them.

According to the literature, pairs tend 1-9 eggs, which hatch after about 27-29 days. The mothers carry newborns on their backs as they swim along, offering a safe perch for sightseeing in safety. The babies fledge after 71-79 days. I did not see any pairs with more than two young, so some were probably lost during the previous weeks.

The grebes eat fish, crustaceans, mollusks, amphibians and insects. Their fishing technique, which was more in evidence in the open water of the Gouwzee, includes skimming the water with outstretched necks and diving underwater. (The neck-to-the-water pose is also used to show aggression but in these cases no other birds were near and they would subsequently dive under to come up with some food.)

The parents demonstrate and the young imitate them, mostly coming up empty-beaked. Occasionally, a parent would fly away and return later with food. The babies eagerly grab the meals offered by both mama and papa.

After breeding, the adults gather together during a molting period, during which they do not fly. Perhaps one day, I’ll be able to watch them in winter and find out new things about them. In the meantime, if you’d like see what happens when they are feeling perturbed, check out my next blog on “The gorgeous grebes when aggrieved and grumpy!”