Learning to love an over-protective bird

When house wrens (Troglodytes aedon) first began visiting my yard some years ago, I was not aware that they are extremely protective parents. I didn’t see them as often as birds of other species since they don’t come to my feeders and were not using nest boxes.

 

The past couple years, however, they have become more comfortable in my yard and began building their nests in boxes after all. This became problematic for me and especially the other species who use the boxes — Eastern bluebirds, Carolina chickadees and brown-headed nuthatches. The reason?

House wrens do their utmost to drive other birds out of their territory so that there is no competition for food needed by their nestlings and fledglings. This protectiveness makes them go so far as to peck other birds’ eggs, which they have done with chickadees and bluebirds in my yard.

Very unfortunately (and upsetting to me), they even killed two nestling nuthatches one year. The other two nuthatch babies managed to fledge. This behavior led a birder, Althea Sherman, to launch a crusade against house wrens in scientific journals in the early 1900s. Now, there are instructions online on how the wrens can be discouraged, for example, on a website devoted to bluebirds.

This year, Eastern bluebirds (Sialia sialis) were tending four eggs in one box and a house wren tried to invade. The parents were very protective and successfully drove the wren away (photo below). Another pair of bluebirds had nested early and managed to guide their young to fledging. They then abandoned my backyard for nesting and the house wrens had no rivals for nest boxes in that area for the rest of breeding season.

House wrens are one of the bird species banded in my yard each year for the Smithsonian Institution’s Neighborhood Nestwatch program. This year the bird bander noticed their nest with babies in a backyard nest box, so she upped the chances of catching one by counting on their extremely protective nature.

A net was put up not far from the box and the bird bander played the call of another house wren. This resulted in both mama and papa wren getting inadvertently caught up in the net while trying to drive away the intruder. They were both banded and then immediately let go so they could resume feeding their babies.

The four woodpiles in my backyard were like a larder for them because they host a plethora of insects.

 

 

And the house wrens are obviously not that choosy about which insects they eat. Mama and Papa brought a large variety to their ever-hungry nestlings.

   

   

 

The parents were also very good at keeping the nest clean.

The three nestlings appeared to be producing numerous fecal sacs so that mom and dad were constantly checking the nest for them and flying them away.

   

At one point, it was interesting that when the male wren brought a large insect to the nest, he handed it over to the female, who was waiting a bit after having just given the babies food.

 

Eventually, the large meal was delivered to the nestlings.

 

As the days went by, the nestlings became louder and more insistent on being fed and the parents scarcely paused in their efforts to keep the meals coming and the nest clean. It must have been a relief for the parents when the babies finally left the nest box because they could now take a breather now and then.

 

Right after fledging, the parents were still busy. The fledglings had not yet flown far so I could see the first post-fledging feeding session for one young wren.

I had learned that house wrens sometimes incorporate spider egg sacs into the nests they build because the hatched spiders eat nest parasites and thereby help protect the developing nestlings! The parents also fed mother spiders and egg sacs to their young. Just after fledging I caught a circle-of-life moment when a parental wren fed a mother spider with her attached egg sac to a fledgling – the death of the poor insect furthered the life of the new bird.

I could see and hear the parent house wrens continuing to feed the fledglings that afternoon. But after a while they appear to have moved to another yard, where they likely weren’t dealing with humans closely watching.

   

The Eastern bluebirds have a new nest in my front yard now with four eggs, so my nest watching can continue for a while. And the juvenile birds of other species coming to the feeders are entertaining, too.

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!

‘Rassing – a surprise visitor – what a delight!

(Warning – this is a bit of a long blog!) Several years ago, what was likely a rufous hummingbird took up residence in my yard during the winter months. That was really unexpected — while it’s not uncommon for migrating or some resident hummingbirds (especially ruby-throats, Archilochus colubris, above) to spend wintertime in North Carolina, particularly along the coast, it’s not so common in the central part of the state. That experience taught me that it’s a good idea to keep up a nectar feeder in the winter as you never know when a stray migrant might show up. In 2015 and 2016, I traveled with fellow birders to visit people who had a buff-breasted (Amazilia yucatanensis) and calliope hummingbird (Selasphorus calliope) wintering at their homes. In actuality, however, I didn’t really expect a rare passerby in my yard.

 

It was consequently with great surprise that I saw a hummer hovering at the nectar feeder last week. “Oh, wow!” I thought; “a ruby-throated hummer is passing through as a very late migrant.” I grabbed my camera to take a few shots and immediately felt perplexed.

 

The bird looked like he had a purple rather than ruby or red gorget (throat feathers). The white patch behind his eye also showed prominently because of his very dark head.

To me, it also looked as if this hummer had blue patches on his tail feathers. (Most say his flanks are green and a hummingbird expert said he has iridescent black tail feathers; the way the light reflects off them made me see blue, however.)

I got a few photos and cautiously asked birding experts on a facebook group if he could possibly be a black-chinned hummingbird (Archilochus alexandri), also sometimes known as the Alexander hummingbird. It seemed unlikely as their normal range is the Western part of the Northern hemisphere, reaching north into Canada (Alberta and British Columbia), east to Oklahoma, and as far south as Mexico, where most spend the winter.

A couple people thought I might be correct, but most thought it was a ruby-throated hummingbird. My spring-summer ruby-throated residents had left at least a month ago but I thought perhaps a late migrant might have arrived. The next day, I saw the bird again and became convinced that it was a black-chinned hummer; his purple gorget was very obvious to me. I posted new photos and now the experts agreed that I was correct. That was very cool – I got a lifer without even leaving my own yard!

 

A couple days later, North Carolina’s hummingbird researcher, Susan Campbell, came to my home to band the unusual visitor. I invited a friend who had been to bird bandings in my yard before to come for the happy event.

Susan arrived early and first set up a cage trap for ‘Rassing (short for the Dutch word verrassing, which means surprise; I wanted him to have a name during his stay 😊). She left the door open with a long string attached and hung the nectar feeder on the outside. It wasn’t long at all before the bird arrived for a drink. When he left, Susan moved the nectar feeder inside the cage.

‘Rassing returned for another drink and flew right into the cage, which Susan shut promptly. She had already laid out her banding materials so she could remove him from the trap promptly.

He went into a small bag (the kind often used to hold birds for banding) which Lucretia held while Susan began filling out the paperwork.

Then the actual banding procedure began. Susan first checked his legs to ensure that he hadn’t been banded already – the hummers rarely show their legs so that was necessary.

Then she got ready to put a thin red metal band on his tiny leg with a silver band showing his numeric code for identification in case he is caught again some time (Band number 7100 (M)-41902).

She checked the length of his bill – 19.19 mm. She also advised that bird feeders with long slits are not preferred even if the birds like them. It turns out that the thin slots can rub against the bill and wear it down, damaging the bill and making it vulnerable to infection. (I afterwards enlarged the slots into ovals and circles and went back to a couple other feeders I had with larger holes.)

She blew on his stomach feathers to check his fat; he was not a hefty bird but certainly a healthy adult male. His weight turned out to be 3.09 g. She also recorded his body length.

She stopped for a moment so I could take a few photos trying to get a good shot of the purple gorget. It looked like ‘Rassing was trembling but this was the vibrations from his rapid breathing. (When resting at 91⁰ F, they take about 245 breaths per minute; at 55⁰ F, this rises to 420 breaths per minute!!) Susan thought he was acting fairly calm.

She measured his short tail (23.5 mm), as well as his wings (40.42 mm). The female black-chinned hummer would have more rounded wing feather tips than this male.

 

Susan took a few photos of ‘Rassing and he got a few long drinks from a feeder held by Lucretia. Then Susan gave me the honor of releasing him – and to my delight, he chose to sit in my hand for what seemed to be at least 90 seconds. I could feel him breathing and it was a real thrill to see him so close. With a little flutter of his wings he took off – and then stayed away from the feeder for quite some time.

 

I added a feeder in the backyard and ‘Rassing began preferentially feeding there – perhaps the front yard had acquired some unpleasant memories. However, at the end of the day, I would remove the backyard feeder so that visitors who wanted to see him had a better chance of seeing him dine at the front-yard feeders.

 

 

A fair number of birders were interested in being able to add him to their life, state and county bird lists, so I offered to schedule visits through a birding listserv for a few people at a time. ‘Rassing appeared more reticent to stay at the feeder when there were more than 2 or 3 people watching, which is understandable. Who wants an audience for each meal and snack you eat??

When it rained, the feathers atop his head clumped together, giving him a new “hair-do.”

 

 

It appears that this species of hummingbird has not been studied much. I found his behavior interesting and spent a good amount of time observing him (chores had to wait). When I watched him leave the feeder and go to a nearby tree, he would sometimes watch me (turnabout fair play, of course).

 

 

He seemed very comfortable with lots of other bird species at nearby feeders. Perhaps it gave him a safer feeling.

‘Rassing tended not to sit on feeders, as ruby-throated hummers often do. Instead, he mainly hovered and vigorously pumped his short tail quite a lot. I learned that this tiny bundle of energy was breathing at a flight rate of about 1260 beats per minute!

 

Occasionally, you could see the band on his leg but mostly he kept his legs tucked into his body.

In the evenings, he came around nearly the same time each day to have a longer drink and then he sometimes perched while feeding.

 

A Cornell University website says that black-chinned hummers rarely stay at a feeder longer than a day during migration, even when food is scarce. In my yard, he had access to lots of bugs (I have a small pond) and three types of sage/salvia were still blooming. Indeed, he sometimes came to the feeder with pollen covering the top of his bill.

Yesterday morning, ‘Rassing apparently had decided it was time to move on. After the warmest Halloween on record in our area, the temperature plunged during the night to the 30s. The next morning was the same and he may have decided it was time to go to warmer climes.

 

I did feel lucky that he graced my yard with his presence for a week; it gave me something to celebrate during a personally challenging time. The oldest known black-chinned hummer was more than 11 years old; if ‘Rassing likes going east during migration, perhaps he’ll stop by again next year – wouldn’t that be a tremendous surprise! 😊

 

Nest Watch citizen science – 2016 edition

Carolina wren Renee and Riley I77A9074© Maria de Bruyn resLast year, I became a Nest Watch volunteer, which involves having birds banded in your yard so that you can follow and report to researchers the birds’ presence over time as they visit and leave your yard.

In 2015, we banded six birds. If a bird is only a temporary visitor or if it died outside the yard due to disease, old age or predation, you just won’t see it again and have no idea what became of it. The American robin (Turdus migratorius) that was banded last year never returned. If the birds stick around, however, you have the enjoyment of observing birds you get to know. The three gray-headed catbirds (Dumetella carolinensis) stayed around all summer and fall, and two of them – Camden and Corey – returned to my yard from winter migration a few days ago. They have been accompanied by females whom they appear to be assiduously courting.
gray-headed catbird Camden I77A8990© Maria de Bruyn res

gray-headed catbird Corey I77A8083© Maria de Bruyn res

Northern cardinal Clancy I77A8123© Maria de Bruyn resOne Northern cardinal (Cardinalis cardinalis) was banded last year, but Clancy only stayed a few days and then disappeared for the rest of the summer, fall and winter. He suddenly appeared yesterday – perhaps encouraged to spend time at the feeders by the other birds with bracelets.

Three days ago, a second round of banding was done and we put the colorful anklets on a total of 10 birds. They were caught in two mist nets – one near my back garden and one near the backyard feeders.

Northern cardinal Camilla I77A9127© Maria de Bruyn resThe nets had just been installed when our first visitor, a female Northern cardinal, was caught. She was not happy and when put in a bag until she could be banded, weighed, examined and measured, she did not remain still and calm. She had a little wait, however, as a female Carolina wren (Thryothorus ludovicianus) flew into the other net at just about the same time, followed by her mate within seconds. As the cardinals can tolerate being in a bag better than the smaller birds, the two wrens were banded first. Alicia let the first one go and then I released the second one, who rested on my palm for a bit. He felt so nice and soft!

Carolina wren Riley IMG_3832© Maria de Bruyn res

Forty-five minutes later, playback of a house wren’s song (Troglodytes aedon) led to the capture of a male who immediately came to investigate who was invading his territory. His mate, who was busy putting the finishing touches on a nest in a box near the mist net, didn’t go near the net.

house wren Hans IMG_3842© Maria de Bruyn reshouse wren Hans IMG_3844© Maria de Bruyn res

A few birds not targeted for the study ended up tangled in a net. A white-throated sparrow (Zonotrichia albicollis) had beautiful vivid breeding colors on his head. A red-bellied woodpecker (Melanerpes carolinus) was not calm like the sparrow, fluttering his wings constantly as Alicia, the bird bander, got him loose.

white-throated sparrow IMG_3837© Maria de Bruyn res red-bellied woodpecker IMG_3822© Maria de Bruyn res

Next up were a male cardinal and a female American robin. Like last year, the birds were measured and weighed. Although about the same length, the weight difference between the heaviest Northern cardinal we banded (41.2 oz) and the American robin was striking (79.6oz). The robin’s fondness for worms and other dietary preferences helps account for this. When I let her go, she didn’t feel very heavy in my hand as she rested a second before flying off.

American robin Raisin IMG_3854© Maria de Bruyn

Except for birds that were molting their tail feathers, Alicia also removed the third left tail feather; this is done primarily for stable isotope analysis, which allows a researcher to estimate where the bird was when that feather was grown.

Northern cardinal Crake I77A0559© Maria de Bruyn res

Carolina chickadee Chancey I77A7762© Maria de Bruyn resThe catbirds avoided the mist nets skillfully this year. Playback of their songs drew them to the vicinity but the two pairs visiting the feeders were more interested in chasing each other away from the territory. Alicia hoped that we could get a Carolina chickadee (Poecile carolinensis); with playback we got a male and then, 45 minutes later after banding another cardinal, we got a pair of them.

Carolina chickadee Chase I77A0348© Maria de Bruyn res Carolina chickadee Chantal I77A9525© Maria de Bruyn res

Alicia blew on the birds’ undersides (forgive the blurry photo) to assess fat reserves, which are stored along the flanks and up near the furcula by the collar bone. She could also determine sex that way and thought that one chickadee might be developing an egg – hopefully, one of the females who lost a nest to predators in my yard a week ago. The last male chickadee released was out of sorts after the experience; before leaving my hand to fly off rapidly, he turned and bit me as a parting shot.

Carolina wren Renee IMG_3813© Maria de Bruyn res Carolina chickadee IMG_3856© Maria de Bruyn res

Alicia had remarked that she hoped no tufted titmouse (Baeolophus bicolor) would be caught; they are not part of the study and she said they are so feisty that their bites can be a bit painful like those of the cardinals. Unfortunately, one leaving a feeder did end up in a net and lived up to its reputation as a feisty bird. A chipping sparrow (Spizella passerina), who was the last bird in a net remained fairly calm as the net was removed from its claws.

tufted titmouse IMG_3858© Maria de Bruyn res

Tufted titmouse IMG_3861© Maria de Bruyn res

Yesterday, I spent some time watching the feeders and yard to see if all the banded birds had left. Luckily, some of them showed up and were here again today. So here are a few of “my birds” with bling – this is a truly enjoyable citizen science project. 🙂

Northern cardinal Clarence I77A0124© Maria de Bruyn res Northern cardinal Crake I77A0593© Maria de Bruyn res

Clarence                                                                       Crake

Carolina wren Renee I77A9354© Maria de Bruyn resCarolina wren Riley I77A0508© Maria de Bruyn res

Renee and Riley Carolina wrens

 

The banded birds are back!

gray catbird DK7A2255© Maria de Bruyn resIn a previous blog, I described how six birds were banded in my backyard so I could track them over time. Bird banding has been done for decades, indicating that it is a practice that truly works for monitoring lifespans and locations of individual birds. But it still seemed to me that being caught in a net, having someone hold you as they extricated your legs and wings from the clinging threads, then putting rings on your legs and sticking you into a container (for weighing) would be a traumatic enough experience for you to decide that this geographical area was not where you wanted to be. Anthropomorphizing the banded birds’ reactions meant that I wouldn’t have been surprised (albeit very disappointed) if I had not seen the six birds again.

gray catbird DK7A2210© Maria de Bruyn resMy expectation was almost immediately proved wrong, however, confirming that birds do not stay away from sites where they were given their ankle bracelets. Corey, my tail-less gray catbird (Dumetella carolinensis) was the first one I spotted again, the very next day after the banding. He has an aluminum band on one leg and 2 red bands on the other.

Since the bands are such different colors, I decided to name the birds as that is easier to note down for sightings. The gray catbird with an aluminum band (they all have this color as it contains their registration number) and white and purple bands became Camden. The catbird with the lovely yellow and green bands was dubbed Clarissa. All three have been very regular visitors to the feeders, proving that a little discomfort was not enough to dissuade them from visiting the always available buffet of mealworms and other delights.

gray catbird Camden DK7A2085© Maria de Bruyn res gray catbird Clarissa DK7A2091© Maria de Bruyn res

The catbirds have a fondness for sweets and like both apples and blueberries. Grape jelly is a real treat, for which they will return again and again.

gray catbird Clarissa DK7A2647© Maria de Bruyn resgray catbird Camden DK7A2198© Maria de Bruy resn gray catbird Camden DK7A1965© Maria de Bruyn resCorey’s return visits have shown how his tail feathers grew in again nicely over time. gray catbird Corey DK7A2472© Maria de Bruyn resI named the Northern cardinal (Cardinalis cardinalis) Clancy and I first spotted him again 2 days after the banding. He has not been a regular visitor, however – or I just haven’t caught sight of him among the bevy of other male cardinals that flit around the trees. However, a few days ago he turned up among the apples!

Northern cardinal Clancy  DK7A7771© Maria de Bruyn res northern cardinal Clancy  DK7A7753© Maria de Bruyn res

Carolina wren Willow DK7A2608© Maria de Bruyn resWillow, the Carolina wren (Thryothorus ludovicianus), has been a very infrequent returnee. When he comes, he tries to stay out of sight, choosing the side of the feeder away from me and only lingering a short while in plain sight. At least I know he is ok.

The one bird I have not yet seen is Rusty, the American robin (Turdus migratorius). I’ve been staring at the legs of every robin that hops around the yard but have yet to see one with leg jewelry. Perhaps he was just a stray visitor the day of the banding? I will certainly keep a look-out for him.

My first re-sighting data were entered into the Nestwatch site on 1 June 2015; it will be interesting to see how long I can maintain this input. Clarissa is a very frequent visitor so I think she will be in many entries. Or perhaps she is just busy right now feeding young ones.

gray catbird Clarissa DK7A2504© Maria de Bruyn res gray catbird Clarissa DK7A2503© Maria de Bruyn res gray catbird Clarissa DK7A2498© Maria de BruynEastern bluebird IMG_3881© Maria de Bruyn resIn the meantime, I am monitoring two nests for data entry; one for Eastern bluebirds (Sialia sialis), who have babies in a nest box, and one for gray catbirds, who have a nest in the middle of a shrub next to my carport.

The catbird parents are ever so vigilant and call out warnings to me whenever I approach the shrub. They hesitate to go into the shrub with food when I am near, even though those babies must be hungry. I finally got a view of them through the twigs when they were close to fledging. They are now hopping around on twigs in the shrub near the nest. Yesterday, when I came too close, Mama catbird dive-bombed, actually grazing my head!

Gray catbird IMG_3887© Maria de Bruyn res gray catbird IMG_3873© Maria de Bruyn

The parents in both pairs are very diligent about bringing the babies meals, working as a team. One catbird parent seems to be good at collecting a variety of foods, in one case bringing three different insects at once (presumably one for each baby). I will look forward to seeing the young ones out and about and sincerely hope my neighbor’s cat doesn’t get them.

gray catbird DK7A2939© Maria de Bruyn res gray catbird DK7A2937© Maria de Bruyn res

Bird watching is an enjoyable way to spend time; doing it and contributing to scientific data collection is even cooler!