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!

 

Craving crawdads in Carolina – a buffet for night herons

Many people in the USA, especially but not only in the South, grow up knowing what crawdads (Cambarus bartoni) are. This was not the case for me. My immigrant family pretty much stuck to the dietary customs of their own and their friends’ home countries (The Netherlands, Belgium, Germany). Like pumpkin pie, sweet potatoes and okra, crawdads were not on those menus and so it was only recently that I actually learned that these crustaceans are the same thing as crayfish, of which I had heard as a child.

This year was my time to learn more about these members of the arthropod family who are related to lobsters – it turned out they were thriving in a pond created through a man-made wetlands installed between a shopping mall and several apartment complexes. I learned about their presence when local birders alerted one another that the crawdads were attracting a family of yellow-crowned night herons (Nyctanassa violacea).

Hoping to spot the herons, I also visited the wetlands and first noted the crayfish remains scattered around near the pond. Shortly thereafter, I came across one crossing a path in another local nature park (photos above and below). It was interesting to see how the crawdad first stayed stock still as I neared and then stood tall on its legs as its tail propelled it backwards while it made a dash for the nearby pond.

The crawdad females lay hundreds of eggs; scientists do not yet know how long they incubate before birth but estimate it takes somewhat longer than a month before they hatch. In North Carolina, there are almost 50 species of these animals and several species are found only in this state.

The crayfish at the wetlands must have had a successful year because the place became a real buffet for various birds. Both adult and young night herons stayed near this pond for quite a long time before leaving to migrate to more southerly climes for the winter.

The adult herons were attractive with their boldly patterned heads.

 

 

   

They kept up their looks through regular preening.

 

 

Sometimes, they emerged from the pond weeds to perch on a snag while peering into the water on the lookout for a meal.

 

It was interesting to learn that while the adults have yellow legs most of the year, their legs can turn red or pink during breeding season.

 

 

In my experience, the younger herons were a bit less shy and didn’t fly off so quickly when I neared.

 

One in particular decided to take the sun in mid-August, adopting a pose that I more often see taken by great blue herons and which I’ve nicknamed the “flasher stance.”

     

The young birds, like their parents, stalked the pond vegetation on the lookout for crawdad snacks.

They also showed the herons’ taste for other food such as snails, earthworms and insects.

 

The night herons, for which most birders visited the wetlands, weren’t the only birds at the buffet, however. Red-shouldered hawks (Buteo lineatus) also showed a fondness for the crustaceans.

 

 

 

The herons weren’t always alert to their presence. One adult, for example, decide to fly to a low perch when chased away from a tall snag by a hawk. S/he settled in for a bit of preening but was then rudely chased off by the same hawk. (That hawk was later harassed by a group of crows, who chased it away in turn.)

Other herons who were interested in outdoor crayfish dining during the humans’ Covid epidemic, included the great blue herons (Ardea herodias).

 

 

Green herons (Butorides virescens) visited the pond regularly as well, eating small fish in addition to the other wetland delicacies.

 

 

 

 

 

 

Belted kingfishers (Megaceryle alcyon) were busy flying to and fro over the length of the pond, but I didn’t see them carry off any crayfish so they must have been focused on fish.

 

A great egret (Ardea alba) was a regular visitor, too, stalking different areas of the pond.

The adult night herons obviously thought it was interesting to watch the egret’s foraging technique.

Other regular visitors to the wetlands included a flock of Canada geese, American and fish crows, Northern mockingbirds and wandering glider dragonflies (Pantala flavescens).

 

There were so many animals feeding on the crawdads this summer that the female crayfish must have had a lot of success with their offspring reaching maturity. The last reported sighting of the yellow-crowned night herons at the wetland was 24 October, but I’m guessing that they will be leaving soon and the pond will not be so busy this autumn. The crayfish population had to have been reduced mightily over the summer season, so it will be interesting to see whether it rebounds and attracts crowds of birds — and birders — next year!

Helping monarch butterflies thrive

If you follow news about nature, you may have come across warnings that the monarch butterfly (Danaus plexippus) has been in rather dire straits for many years now.

 

These lovely orange and black butterflies live from 6 to 8 weeks when they are adults engaged in reproduction. Those who live in the Eastern USA participate in a multi-generational migration process between Canada and central Mexico. The last generation to emerge in late summer is able to delay its sexual maturity to undertake the last leg of the migratory journey (called reproductive diapause) and may live up to 8 months. Individual butterflies may travel as far as 1200-3000 miles to get to their warmer over-wintering grounds.

 

Since the 1980s, the Eastern US monarch population has declined by about 80%, mainly because the only food source for their caterpillars has been disappearing. Milkweeds used to grow abundantly in agricultural areas and along roadsides and ditches, but people have been eradicating the plants from fields and using herbicides and mowing to remove them along roads.

Climate change has also affected the butterflies’ breeding and migratory patterns so that reproduction has been reduced.

One way to help out the monarchs is to plant native (not exotic!) milkweeds in your own yard and any other natural spaces to which you have access. I’ve been doing it around my home and as a volunteer for the Mason Farm Biological Reserve. This year, I was lucky enough to be a beneficiary of a milkweed give-away organized by some local high-school students, so I had two types of the plants in my yard.

 

The ones that I had originally planted were common milkweed (Asclepias syriaca). These plants have large globular clusters of flowers that range in color from pinkish to purple. They do not have blooms their first year but that doesn’t stop the caterpillars from eating their leaves.

 

Butterfly weed (also known as butterfly milkweed; Asclepias tuberosa) is a bit more delicate and “exuberant” in appearance, with small clusters of orange, reddish and yellow flowers. These were the plants that I was gifted by the students and I was happy to see them grow quickly to exhibit their beautiful blooms.

According to Wikipedia, the butterfly milkweed is not a preferred plant for the monarch but this year the butterflies seemed much more attracted to it than to the common milkweed. After a few visits from some butterflies, I began seeing caterpillars and at one point counted 17 crawling up and down the various plants.

They were especially prevalent on the butterfly weed in my front yard and were munching the plants to bare stems very quickly.

 

       

To make sure they had enough food, I transferred some of them to the common milkweeds in my back yard – these were larger plants with much broader leaves and I thought this would ensure their healthy development. Frass (poop) was being left on the remaining leaves and the ground surrounding the plants.

 

It was rewarding to see three caterpillars make it to the chrysalis stage; the other caterpillars crawled away before I could see where they went, and I didn’t find them suspended from any plants. The first one had attached itself to a bare sapling and, unfortunately, the next day it had disappeared, leaving only the silken thread by which it had been suspended.

The caterpillars store milkweed glycosides in their bodies, making them toxic to many other animals. They still have many predators, however, including wasps, spiders, other insects, lizards, toads and mice. I resolved to save at least one chrysalid if I could.

I got to see the second chrysalis being formed (see the video, which is a little shaky at times). When the caterpillar is ready to undergo the pupation stage, it attaches itself to a plant stem by making a silk pad as an anchor (called a cremaster). Then it inserts the hooks at the end of its abdomen into the pad and hangs down. When the caterpillar forms a J shape, this signals the change to a chrysalis will soon be underway.

Starting from the head, the outer skin is shed, rolling up as the new covering develops. The shed skin may remain at the silk pad or fall off.

 

Slowly the stripes of the caterpillar disappear, and the chrysalis takes on a shiny even green hue, with some golden accent spots.

 

I kept that chrysalis, as well as a third one I saw the next morning, in my house and waited for them to darken. This signals the butterfly is almost through developing inside.

One morning I found the newly emerged monarch from the second chrysalis drying its wings. I took it outside so that it could fly free and then begin its trip to Mexico. (I also took the third one outside when it darkened but the twig holding it disappeared.)

 

You, too, could contribute to their propagation by planting some milkweed if you have an area for this. Autumn is the best time to plant seeds, but you can try it in the spring as well. Common milkweed typically doesn’t flower during its first year, but butterfly weed will give you flowers in its first season; the latter plants may be slow to emerge at first.

Both of these milkweed varieties are perennials so be sure to remember where you planted them. Common milkweed may spread out with time, while butterfly weed remains where you put it.

 

Other flowering plants will attract the adult monarchs, too, for nectaring, such as asters and lantana.

 

And then sit back next year and wait for the monarchs to arrive, happy in the knowledge that you have contributed to maintaining a favorable environment for their survival.

More ideas on how you can participate in the drive to save this iconic butterfly are detailed on a U.S. Fish & Wildlife Service website: https://www.fws.gov/savethemonarch/

 

What gets a birder really going? A rare bird!

People who are “into birding” are excited when they see a new bird for the first time. Many keep “life lists” – an account of each different species they have actually seen worldwide, in their country, in their state or province, or perhaps in their yard. When they see a new species, birders say they got a “lifer” – a first-time sighting in their life. Quite a few of these birders then decide to enjoy a reward – a lifer pie!

This past week, I was lucky enough to get a lifer, thanks to alerts circulated in the birding community. Doc Ellen Tinsley, the North Carolina Piedmont area’s main bald eagle researcher, also looks for other species when she goes out to see the eagles she knows. On 27 September, she was at the Jordan Lake Dam, where she often sees eagles whom she has come to recognize and know. Since it is the migration period for many birds that breed up North, she was also watching for warblers, a popular type of songbird because they are often beautifully colored.

She counted herself very lucky when she spotted a yellow striped bird that she had not seen before. After getting a confirmation of its scientific identification, she notified area birders that she had spotted a Kirtland’s warbler (Setophaga kirtlandii) and it was still foraging so people might be able to see it if they came to the Dam.

Until recently, the Kirtland’s warbler was considered an endangered species as it requires a very specific habitat in jack pine forest to breed. It depends on areas affected by fire; about 6 years after a conflagration, the space will be regenerated with small trees, shrubs and open areas that are favorable for its nests. When trees grow to about 10-16.5 feet high (3-5 m), the warblers leave to find a more suitable living area.

Compared to other birds, the Kirtland’s has the most restricted geographical breeding area of any bird in the continental United States. In the 1970s and 1980s, only about 167-200 males were counted in annual surveys. Conservationists in Michigan, Wisconsin and Ontario, Canada, collaborated on protecting the Kirtland’s environment and achieved success. This warbler has now been re-designated a threatened rather than endangered species. There are currently about 2,300 breeding pairs who migrate south to spend the winter in the Bahamas.

 

These birds’ diet comprises mainly insects and small fruit such as blueberries. Occasionally, they will catch an insect on the wing but more usually they glean pine needles and other vegetation for their meals. Spiders, moths and flies constitute part of their diet. Adults will also ingest pine sap.

 

 

These birds place their nests on the ground, underneath the small jack pines. The males will feed the females while they brood and both parents bring nutrition to the hatched offspring. In the past, brown-headed cowbirds often laid their eggs in Kirtland’s warbler nests and this contributed to their endangered status. Elimination of cowbirds from the environment for many years has now reduced the threat.

“As a condition for the warbler’s delisting, the USFWS, U.S. Forest Service, and the Michigan Department of Natural Resources signed a memorandum of understanding that the agencies will continue habitat management at sufficient levels to ensure a continued stable Kirtland’s Warbler population. Keith Kintigh, a forest conservation specialist with the Michigan DNR, says his agency will plant 1.8 million jack pine seedlings per year going forward to help maintain the 38,000 acres of suitable jack-pine habitat needed to keep the warbler population above the 1,000-breeding-pair threshold for recovered status.”
9 January 2020; https://www.allaboutbirds.org/news/kirtlands-warbler-delisted-after-47-years-of-conservation-work/

It’s likely that at least 100 people have traveled to Jordan Lake Dam to see this female bird. She was very popular because she didn’t particularly hide as some birds do. (She was sometimes a bit hidden by the pine needles, but that was because she was constantly moving about in the trees.)

She was foraging for insects along rocks bordering the dam area and in nearby trees, which gave the birders an opportunity to memorialize her visit with photos. Much of the time, she was seen in the company of a male bird of the Cape May species, who look similar (left).

The Kirtland warblers’ areas in Michigan and Wisconsin are closed to the public when they are breeding. They are rarely seen so there are guided tours in those two states to enable people to spot them.

 

Doc Ellen provided area birders with a wonderful opportunity to admire this rare bird! A much needed bright spot in a year that has been fraught with calamities.