A third look at our 2020-21 “superflight” irruption – red crossbills

As mentioned in my last couple blogs, finches that usually reside in Canada and the northern USA have come south this year because of a dearth of food in their usual habitats. One of the factors contributing to the shortage is the varying cycles in which cones, seeds and fruit ripen among different tree species.

Not every tree produces an equal amount of seeds or berries every year; for example, this year my red cedars didn’t have very many juniper berries and by the time the cedar waxwings arrived, the American robins (Turdus migratorius) had already cleaned out the crop. Periodically, many of the different tree species up North have low seed production at the same time, so that birds who eat different kinds of crops all need to go elsewhere for sustenance in the winter.

An interesting speculation from scientists in the Finch Research Network is that this synchronized low seed production evolved as a means of limiting food supplies for seed-eating (red) squirrels who could reproduce greatly and then wipe out all the seeds so that no new trees would grow. Jamie Cornelius, a researcher at Oregon State University, explained that “birds are mobile, and can find cone crops somewhere else,” while the sedentary squirrels then need to curtail their reproduction. In addition, some birds have evolved biological processes that make it easier for them to cope with food scarcity.

Red crossbills (Loxia curvirostra, called common crossbills in Europe) molt quite slowly, losing only a few feathers at one time, which makes it possible for them to fly elsewhere at any time in search of sustenance. They are normally not migratory but will travel for food, so in December 2020, local birders were quite excited when red crossbills were spotted at a state game lands in a neighboring county.

I was not enthusiastic about going to a hunting zone but had heard that the duck hunters were usually only busy early in the morning. So I donned my bright orange vest and ventured out on the two-mile walk to the spot where the crossbills had been seen. I waited around for a couple hours but they didn’t show, although I was looking for the reddish males and yellow females to make an appearance.

I didn’t give up. On my fourth visit to the game lands, I finally saw the crossbills (although I didn’t realize it immediately as they were so far away and my cataracts make seeing anything distinctly at a distance quite difficult. It was only after I enlarged one photo on the camera that I saw what they were! Remember, you can see a photo larger if you click on it and then back arrow to the blog).

I first thought perhaps some grosbeaks had flown in, so I focused as well as I could on the distant trees and took photos. I was thrilled to see that I had finally photographed those elusive birds – giving me a “lifer” for 2021. 😊

Sometimes it’s not easy to understand why a certain bird species has a particular common name. For example, many people would call a red-bellied woodpecker a red-headed woodpecker because the red on the head is much more noticeable than the hue on its belly. But the crossbills exemplify their common name quite accurately with their upper bills that curve down over their lower bills. A good view of their beak can be seen at the All About Birds website.

At first sight, one might think that this beak arrangement would make it difficult for them to eat, but this morphological adaptation means that they can extract seeds from conifer cones that are still closed, which other finches cannot do. Their bill structure makes it possible for them to hold onto a cone, pry it open with their beak and then take out the tightly-packed conifer seeds with their tongue.

This specialized anatomical feature does restrict the crossbills’ diet somewhat. They do eat some other seeds, berries and insects from time to time and they also ingest grit and sand from time to time as having these substances in their crop helps them to digest the conifer seeds.

What also makes these finches very unusual is that there are at least six – and perhaps as many as 11 – sub-species in North America who differ in the size and shape of their beaks and the type of calls they make. Their unique vocalizations has led to each sub-group being designated as a “call type” and each type feeds on a different conifer species. They move about in groups and call to each other while flying from tree to tree. Some scientists think they may be communicating about the feeding possibilities in each cone-laden tree they pass!

Another behavior that is distinctive for the red crossbills is that they breed at any time of the year, whenever sufficient food supplies are available. When a female and male form a breeding pair, they imitate one another’s flight calls so as to keep track of one another.

 

Unfortunately, unlike other irruption species such as evening grosbeaks and pine siskins, the red crossbills are rare visitors to bird feeders.

When I heard that crossbills had been seen at a game lands area much closer to my home, I made a couple more treks in hopes of spotting them. The first day I was incredibly lucky as I was the only person visiting the reserve and could walk at a leisurely pace in quiet fields except for the chittering of multiple bird species, including a hermit thrush.

Unfortunately, I didn’t manage to see any crossbills flying overhead. Another visit to this nearby game land was shortened considerably when I discovered it was quite noisy with two hunters accompanied by a pack of baying hounds who were yowling very loudly and frequently. I high-tailed it out of the reserve and resolved to be happy with my one and only crossbill sighting (so far). Hopefully, one day I’ll be able to see them more closely – something to which I can look forward with great anticipation!

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!

Some beauty to offset a distressing week

This past week in the USA has been rather distressing as far as health and politics are concerned. The COVID epidemic is wreaking havoc and then humans wrought havoc during a procedure intended to be part of a peaceful transition of governmental power. So we can all use a bit of distraction to remind us there is also still beauty in the world and I’ll end my last trio of posts with one more view of hummingbirds – this time featuring the one species that visits my home every year, the ruby-throated hummingbird (Archilochus colubris).

Fortunately, my yard now has several types of plants that offer the hummers natural nectars to complement their primarily insectivorous diet.

The rose of Sharon (Hibiscus syriacus) flowers are a popular feeding site.

They are also fond of the blue-black sage (Salvia guaranitica). My original plants were a gift from birding friend, Gail; now they are growing in four areas of the yard. Sometimes a hummer doesn’t want to hover but uses a nearby prop to offer some less strenuous feeding. And then the bird can close its eyes to thoroughly enjoy the sweet sap.

Hot lips sage shrubs (Salvia microphylla ‘Hot Lips‘), which I got at a garden center, have proved to be popular feeding sites. This is quite a hardy plant.

The hummers also like going to the lantanas (Lantana) and the yellow passionflower (Passiflora lutea), which kindly came to my yard on its own.

 

Another popular plant is the butterfly bush (Buddleia davidii).  Many recommend against planting this bloomer because it can be invasive. However, some garden centers have developed varieties that scarcely seed and that must be what I luckily got as it has never appeared anywhere else in the yard in more than a decade.

It also attracts butterflies, bees, syrphid flies and hummingbird moths, so I’m quite happy with my butterfly bush.

The ruby-throats also do like their nectar, however. After visiting various flowers, they often take a seat near or on the nectar feeder so they can sip at their leisure.

 

They will also do their best to keep other hummers away from the nectar feeder — even when I have as many as three or four feeders available.

They keep an eye out for intruders.

When a rival appears, it can lead to confrontations. Mostly these involve aggressive displays and chasing one another; only very rarely have I seen them actually physically engage.

This past summer, a few laid-back moments occurred when they tolerated one another.

It’s not only the males who are aggressive; female hummers can also be quite protective of feeding grounds. This past year, it seemed that I had mostly males visiting. While a female hummer can have one or two red spots under her chin, usually that is the beginning of a young male developing his ruby-throat.

It can be fun to watch as more spots appear with passing days.

 

Eventually, the males get their fully developed gorget, which can be quite stunning.

The red hue is very dependent on how the light hits their feathers. In some cases, the red feathers almost look black.

  

The hummers take care to groom their feathers.

They take advantage of the rain to have a shower.

There are times when they look a bit scruffy, however. That is when they molt. This process of replacing old feathers with new ones usually takes place on their wintering grounds. This past summer, the hummers seemed to have lingered longer than usual and began molting before their trips further south.

White feathers appear more and more as molting proceeds. And feathers come loose before falling away.

They can look a bit scruffy during this time.

Eventually, they get back to their pretty selves. It always stays fun to watch them flying — at least for me. That is when you can see their tiny feet better.

And you get an idea of how rapidly their small wings move as they hover and soar.

They can beat their wings up to 70 times per second!

It doesn’t seem to me that I’ll ever tire of watching these tiny fliers; they always are entertaining. I hope seeing some photos of them in action have provided you with a brief respite from the worries of the world, too.

Flying shades of bronze, brown and copper

While the hummingbirds “clothed” in vibrant green and blue hues in Costa Rica are really wonderful (previous blog), I found out that I’m really attracted to some hummers with more subdued hues as well. The photo above is probably my favorite hummingbird photo of my 2019 trip — that long-billed hermit (Phaethornis longirostris) was simply gorgeous!

Before showing you some other shots of this stunner, let’s look at some other hummers with hues of bronze and copper. The rufous-tailed hummingbird (Amazilia tzacatl) is a smaller bird but a pleasure to see as it flits from bloom to bloom.

These medium-sized hummers defend their nectaring territories vigorously, which may lead to some ruffled feathers. Scratching an itch can also lead to the same condition.

The bronzy hermit (Glaucis aeneus) has a long, curved bill which is useful for the types of flowers where it seeks nectar. It is known to be a fast flyer and is said to only stay a few seconds at each feeding site, so I feel lucky to have gotten a photo of it!

When I saw the black-bellied hummingbird (Eupherusa nigriventris), I immediately fell in love.To me, it looked like this male had had a crew cut and then covered himself with black velvet.

The females of the species do not have black bellies but are also pretty.

Another species that really caught my fancy was the brown violetear (Colibri delphinae). They are very muted in color, which is what makes the color patches really stand out.

The blue-green throat feathers shine. And the violet stripe behind the eye is certainly eye-catching!

It must be the real contrast between the overall subdued coloration and the vivid color patches that attracts me. As other birders moved on, I stayed behind to watch them for a while.

I would enjoy seeing this hummer in person again!

I will leave you with a couple more photos of the wonderful long-billed hermit. The lengthy curved beak and long tail feathers make for a very attractive presence.

And this elegant hummingbird also has a distinctive mating behavior. Up to 25 males will gather in a lek (a communal area where courtship displays are done) and begin wiggling their tail feathers. They then compete to sing a song that will induce a female to choose them as the sire for their young!

Seeing a courtship contest among the long-billed hermits must really be a wonderful experience. But I’m just glad I got to see this species at all and hope perhaps to do so in person one more time!

Next blog: one more view of hummers — this time in North Carolina.

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. 😊