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!

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.

Kinglet capers – finding food and enjoying short rests

It seems that at least once a year, ruby-crowned kinglets (Regulus calendula) feature in my blogs; they are one of my favorite bird species and I always enjoy seeing them again and again.

These small birds are bundles of feathered energy, almost constantly in motion as they seek insects, which form the bulk of their diet.

 

They are only slightly larger than ruby-throated hummingbirds: 9-11 cm (3.5-4.3 in) long versus a length of 7-9 cm (2.8-3.5 in) for the hummer.

When they scour the vegetation for food, they may be flicking their wings continuously.

Fortunately, they do take little breaks now and again, so we can admire their beauty.

These breaks often last less than minute, however, and often are even briefer so you have to be ready and waiting to capture a photo.

I’ve been lucky this fall to find a few spots where I know some kinglets are hanging out, so I get to see them quite regularly.

My yard-visiting kinglet has returned for the winter season as well; I usually see him mostly at the suet feeder, where he will hover like a hummer as he takes quick bites of peanut-flavored vegetable lard laced with grits, oatmeal and nuts. He is a bit more gray in color than many other kinglets.

I’m wondering if this year’s bird is the same one who has been here the last 5 years. Unlike my previous visitor, I’ve seen him take a seed from a feeder as well. This has not happened before, even though it is known that they eat berries and seeds in winter.

This year’s bird also seems a bit shyer than my kinglet(s) from previous years. When I lift up my camera, he tends to take off. My resident the last years was not shy at all, a couple times actually perching on the suet feeder as I carried it to the pole. Still, my yard visitor’s anxiety has been nowhere nearly as obvious as that of another kinglet whose story I will relate in the next blog!

 

Summer hummers – entertainment for free: part 2

In my yard this summer, the ruby-throated hummingbirds (Archilochus colubris) came late to the feeders (similarly to what other people in the area had reported). Now, there are at least four vying for the four feeders, claiming territory for their own.

 

 

One bird in particular is most likely to be seen enjoying the garden flowers, including blue-black sage (Salvia guaranitica) and hot lips salvia (Salvia microphylla ‘Hot Lips’). In the first two photos below, you can see as his throat starts to bulge more as he sucks up the sweet nectar to complement his mostly insectivorous diet.

 

 

The airborne nectar droplets indicate that sometimes this hummer is a messy eater — or must leave quickly as another hummer is almost literally on its tail.

A couple of the birds spend a lot of time near the nectar feeders, perching close by to chase off anyone who comes near.

 

 

 

They each have favorite perching spots from which they can observe if an “intruder” is coming near the feeder they have claimed.

 

 

Sometimes, they fly up to a higher perch so they can see both the front and back yards – a necessary vantage point if they want to keep an eye on where everyone is.

 

Most ruby-throats have 940 feathers, all of which are replaced each year. As they take little rests, they stretch their feathers and may also groom them.

When a rival approaches, they spread their rectrices (tail feathers) – both when sitting and in the air.

 

Their feathers are beautifully arranged, looking like scalloped decorations.

 

They make frequent trips to the feeders and then occasionally “air out” their tongues.

 

The bill of the ruby-throated hummingbird is one of its most distinctive features. It measures about 0.59-0.79 in (15-20 mm) in length and is said to open no more than about 0.39 in (1 cm wide) at the tip. The hummers in my yard seem to be able to open their mouths to varying extents, however. They consume nectar by extending and contracting their tongues up to 13 times per second.

 

 

 

A quick, only few-second nap is also a frequent behavior. The hummers are almost constantly at the feeders and thus bulking up for their long migration, but they also expend considerable energy chasing one another away from feeders and flowers!

 

 

 

The hummers are not fazed by weather, zipping around rain or shine. Putting on weight and strength for their autumn migration down south is important for survival!

These minute marvels are such a pleasure to watch; I will certainly miss them when they begin their journeys to their wintering grounds.

 

Summer hummers – entertainment for free: part 1

 

When a hummingbird other than a ruby-throated hummingbird (Archilochus colubris) is seen in the Triangle area of North Carolina, it is listed as a rare bird on the Cornell Lab of Ornithology listserv. One year, I did have a chance to see a buff-bellied hummer visiting in a nearby town though; another year a rufous hummer frequented my own feeders in the winter. Mostly, however, it is the ruby-throats who take up residence at my address, which is just fine as these feisty tiny birds provide loads of entertainment.

 

During a trip to Quebec earlier this year, we also saw ruby-throated hummingbirds there – early arrivals during the spring migration.

 

A few years ago, one of my blogs focused on their preening and cleaning, so this time I’ll mostly feature some of my favorite photos of them taken this summer in various places. (When looking through the shots, I had a LOT I liked, so this is now going to be a 2-part blog!)

At Sandy Creek Park in Durham, one female hummer had made a coral honeysuckle (Lonicera sempervirens) one of her preferred dining spots.

 

 

A butterfly garden featuring blue-black sage (Salvia guaranitica) and bee balm (Monarda) also attracted her and some other hummers.

 

One female found the bee balm to be a good place to rest, understandable since these bundles of energy have a high metabolic rate. Their hearts beat up 1260 times per minute and they take about 250 breaths per minute even when they are resting! Taking a few sips while remaining perched has to be a welcome luxury.

 

 

 

 

The hummers’ main wing bone, the humerus, is adapted to hovering flight and they have very large deltoid pectoral muscles relative to their size.

 

 

Male birds produce sperm that flows through the vas deferens (sperm duct) to the cloaca. When they mate with a female, they transfer sperm by touching the tip of their cloaca to that of the female; they do not have a penis. Females only have a functional left ovary; the right one atrophies early in her development, which allows her to avoid the extra weight of a second ovary and makes her lighter for long migratory flights.

One big treat for me this year was finding two ruby-throated hummingbird females tending a nest, the first time I had been able to spot this.

 

Later, I was able to take a quick photo of one female collecting cattail fluff with which to line her nest.

Even when several ruby-throats are frequenting an area, the (temporary) coloring of their feathers can help distinguish them. This young male had a few olive-green dots under his eye and a bit of white on the crown of his head.

 

A somewhat more mature male has a little white patch behind his red gorget.

 

They are all little beauties! Second part of this blog is coming up and then on to Costa Rica!