The birdy breeding cycle 2020 – 4: growing into adult plumage

As mentioned in a previous blog, when young birds are ready to leave the nest, they don’t necessarily look like their parents. Many of the altricial birds (ready to move about and forage on their own) may resemble fluffy versions of the adults, as is the case with these hooded merganser ducklings (Lophodytes cucullatus) following their mother.

The brown-headed nuthatch babies (Sitta pusilla) look very much like their parents. Sharp-eyed observers might notice that the tops of their heads are not as brown as those of their parents.

The Eastern meadowlark juveniles (Sturnella magna) resemble their parents but lack the bright yellow and black coloring on the throat and breast.

 

The difference between adult and juvenile downy woodpeckers (Picoides pubescens) is subtle. The female woodpecker has no coloring on the top of her head, which is simply bedecked with the white and black feathers that cover the rest of her body.

The male woodpecker has a red patch on the back of his head.

The immature woodpecker has a red patch on top if the head and this is lost as the bird reaches adulthood.

The Northern mockingbird youngling (Mimus polyglottos) resembles mom and dad quite a bit except for some spotty streaking on the chest.

In other species, the babies start out looking quite different from their parents. Spots characterize many members of the thrush family, with birds like wood thrushes (Hylocichla mustelina) and hermit thrushes (Catharus guttatus) retaining the spots in adulthood.

   

The Eastern bluebirds (Sialia sialis) and American robins (Turdus migratorius), on the other hand, are only strongly speckled as immature birds, losing their spots as they mature.

In some cases, the birds undergo color changes. Male summer tanagers (Piranga rubra) start out yellow-orange with their reddish coloring appearing in patches until they finally achieve their very bright adult red hue. Some of the immature birds are really quite beautiful with their mottled colors.

 

   

The male blue grosbeaks (Passerina caerulea) start out brown and gradually achieve their dark blue feathers with some reddish/brown wing accents.

 

 

Among the birds that undergo a major change are the European starlings (Sturnis vulgaris). The young birds start out with dullish brown or gray hues with some streaking. Eventually, they begin to develop some spotting and then ultimately achieve the beautiful adult summer glossy feathering with green and purple hues mixed in.

 

 

The females of the Eastern towhee species (Pipilo erythrophthalmus) have a brown back above a white breast with reddish sides, while the males have black backs.

The young developing towhees keep you guessing as to their sex since they undergo quite a lot of color changes as they develop. They do have the white in their tails, which helps you identify them as to species.

 

  And then we come to the hawks and owls. It is not unusual for the young raptors to look nothing at all like their parents. The red-shouldered hawks (Buteo lineatus) start out looking like fluffy and then becoming gradually kind of scruffy looking.

     

As they get a little older and leave the nest, they start to resemble their parents more but have more streaking on the breast. As they near adulthood, they look much more like mom and dad.

 

And we end with an example of another raptor. There is a real difference between the baby great horned owl (Bubo virginianus) and its parent as you can see. Many birds are impressed by the adults but ooh and aah over the nestlings. It must be the combination of those big eyes and fluffy feathers that take away attention from the already formidable claws!

               

Next up – a foray into the world of amphibians and reptiles!

The birdy breeding cycle 2020 – 3: raising young

This year, most of the birds that visit my yard chose to build their nests in places where I didn’t see them. Only the brown-headed nuthatches, house wrens and Eastern bluebirds chose to use nest boxes. The Carolina wrens (Thryothorus ludovicianus) began to use a nest box but their nest was invaded by ants before I had noticed so they abandoned that site. Still, I was able to watch parents with babies, both at home and out on the nature trails.

There are two major kinds of baby birds. The altricial birds hatch as helpless young who must develop their sight and feathers, requiring parental care until they can fly from the nest. They include the songbirds that you may see often, such as chickadees, nuthatches, cardinals and bluebirds, whose babies are seen below shortly after hatching and after several days of development.

 

In contrast, the precocial bird babies can quickly move about on their own after hatching and are able to begin foraging for food themselves as they follow their parents around. In some cases, the parents may also feed them. Examples of precocial birds include killdeer, ducks and Canada geese (Branta canadensis) as seen below.

The nest I watched most closely this season was built by brown-headed nuthatches (Sitta pusilla) in a nest box. Carolina chickadees were also interested in that spot, but the nuthatches won out. Mama Nuthatch laid six eggs, four of which hatched. She and Papa were very hard workers, flying to and from the box countless times per hour. Like other seed-eating birds, they fed their nestlings insects because the babies need lots of protein for their development.

They were devoted parents, flying to and fro with food, carrying away fecal sacs and chasing off other birds who used the nest box as a perch. All their care was no match, however, for a pair of birds who are known to be quite aggressive during nesting season.

I first learned of house wrens’ (Troglodytes aedon) intolerance of other nesting birds in their vicinity when they invaded the nest of a banded female Carolina chickadee (Poecile carolinensis), whom I had named Chantal. Her babies were hatching and the wrens went into the nest during her absence and killed them. That experience made me hope they would not return to my yard the next spring, but they seem to like the area. This year they visited all the nest boxes in my yard and the male began nests in several of them to keep away other birds. It is thought they may drive away other nesters in order to reduce competition for food when it comes time to raise their own young.

The wrens finally settled on a nest box and I thought they would leave the nuthatches alone. Their young ones got to the brink of fledging and the parents were encouraging them to fly out. Sometimes, they would fly up to the box as a youngster peered out into the big wide world and just hover with the food in their mouth.

They would perch atop the box and call. Eventually two took the leap (which I didn’t see); I thought the others would follow the next day. The parents were busy in the morning and suddenly all activity ceased. I guessed that the other two had taken flight, so in the afternoon I took a peak in the box. To my utter dismay, I found the remaining two nestlings deceased; the wrens had pecked them to death. ☹ I buried them in my flower garden with a small Buddha statue marking the site.

The nuthatches continued taking care of their fledged babies. They would follow the parents to the feeder poles, crouch down and flutter their wings rapidly as they begged for a morsel.

Eventually, the parents found a nearby branch in a large willow oak where they would crack nuts and feed their offspring. As you can see, the spot got a lot of use and could be easily identified by the shredded bark. The whole family still goes up there to eat their nuts from the feeders!

Many adult birds appreciate bird feeders as “fast-food” stops for themselves while they spend most of their time searching for meals for their nestlings. Even the species who mainly eat seeds feed their babies insects because the young ones need lots of protein as they develop toward maturity. The Eastern bluebirds (Sialia sialis) in my yard and other areas seem to favor caterpillars as a food of choice for their developing youngsters.

 

The pileated woodpecker parents (Dryocopus pileatus) take turns sitting on eggs and bringing food for their young ones.

The larger raptors bring in heftier meals for their offspring. This red-shouldered hawk grew up alone; those of us watching the nest didn’t know whether only one egg hatched or something happened to a sibling. The parents would bring small mammals for the baby to eat.

 

A pair of great horned owl babies (Buteo lineatus), located by Mary, a locally well-known bird photographer, appeared to be growing well the couple times I went to see them. I never saw the parents bring them food but assume they were well fed as they were venturing out of the nest the last time I saw them (a process called “branching”).

It seems that a young bird’s open mouth is a trigger for parents that they can barely resist. Until they mature, the fledglings have a pale white or yellow area, or in the case of American crows (Corvus brachyrhynchos) reddish, where their beaks join. This becomes very visible when they open their mouths wide to beg for food and parent birds have a hard time resisting the urge to stuff food down their throats.

The Eastern phoebes (Sayornis phoebe) at a local park were following their parents around asking for food.

They exhibited both the crouched wing fluttering and wide-open mouths as cues that they wanted to be fed.

  

The downy woodpecker (Picoides pubescens) juveniles did not seem to beg as much as the other birds in my yard. They just perched close to feeders or their parents and eventually mom or dad gave them a bit of suet.

The European starling young (Sturnus vulgaris) are especially demanding to judge by their behavior at my feeders. These are larger birds and the offspring are as large as their parents,

They are capable of feeding themselves but spend a good deal of time with wide open beaks demanding to be fed.

 

The starling parents usually give in, but you can almost think they look exasperated.

At least the immature starlings can demonstrate well how a bird looks with a full crop (i.e., the enlarged part of the esophagus that forms a muscular pouch in which food can be stored).

In between all the feeding, the parents have one other important nest duty – keeping the nest as clean as possible. They do this by removing fecal sacs, as this prothonotary warbler (Protonotaria citrea) was doing last year.

 

Some adult birds will actually eat the fecal sac. This is because the nestlings do not completely digest their food and the sacs therefore still contain valuable nutrients that the parents can use. I can imagine the parents are glad to be done with this duty once their young have fledged, however.

When you’re out walking or watching bird feeders, it can be entertaining to observe the birds as they nest and raise their demanding children. And it’s good to know that you may even see adult birds begin to drive away their babies, either because they’re tired of feeding them or because they are busy with a second or even third brood for the season.

The birdy breeding cycle 2020 – 2: nest-building

After courtship has taken place, the various bird species get down to the work of constructing nests for their upcoming broods. Even now in July, gray catbirds (Dumetella carolinensis) have been gathering up nesting materials, as have house finches (Haemorhous mexicanus) who have been followed around lately by the members of their first brood.

gray catbird P6147926© Maria de Bruyn res

house finch P7081079© Maria de Bruyn resThe sites they choose can vary considerably. Canada geese (Branta canadensis) tend to locate their nests at the edge of ponds if possible. In one case, a pair built their nest atop a beaver lodge.

Canada goose P4269282© Maria de Bruyn res

Canada goose P4070275 © Maria de Bruyn res

Ospreys (Pandion haliaetus) like to place their nests atop tree snags and will also use special platforms constructed by people for them. A radio tower or stadium lights, such as those at the right, will also do nicely, however.

osprey P5044393 © Maria de Bruyn res              osprey P6126775© Maria de Bruyn res

Northern cardinals (Cardinalis cardinalis) often choose shrubs and bushes; this one built her nest in a Japanese honeysuckle vine that I allowed to grow along the top of a fence surrounding my berry garden.

Northern cardinal 2G0A0652 © Maria de Bruyn res

Northern cardinal 2G0A0001© Maria de Bruyn res

Killdeer (Charadrius vociferous) seem to take the least effort in securing a spot for their nest. It is not uncommon at all to find them scratching out a very shallow depression in a parking lot, pathway or bare bit of ground. This killdeer put her nest on a patch of ground at the edge of a parking lot and, admittedly, it was not very obvious (Look carefully at the center of the photo).

killdeer eggs IMG_2885© Maria de Bruyn res

Nevertheless, people were walking across this patch of ground with their kayaks and canoes that they had just unloaded and the eggs were in danger, even if the parents did their broken wing display to try and lead people away from the area.

killdeer 2G0A8192© Maria de Bruyn res

I found a couple traffic cones and marked off the area, warning someone who had just parked nearby. Then I contacted the park rangers to tell them about it.

killdeer cones IMG_2887© Maria de Bruyn res

Fortunately, the rangers added a third cone and some tape to effectively cordon off the area.

killdeer IMG_5577 © Maria de Bruyn res

Carolina wren eggs IMG_1173© Maria de Bruyn resThe prize for weirdest nest sites will, in my humble opinion, always go to the Carolina wrens (Thryothorus ludovicianus). People in birding groups often post messages about these birds having built a nest under the hood of a car, in an old boot left outside, inside a little-used mailbox or on a door wreath or plant pot. I have a full-sized spare tire atop a tool cabinet and last year, the wrens laid eggs there.

This year, on one of my walks, I discovered wrens who were feeding their babies in a very awkwardly placed nest inside an old cable or wire box on a neighborhood light pole.

Carolina wren P5086279© Maria de Bruyn res     Carolina wren P5181735© Maria de Bruyn res

When I visited some time later, the nest was empty so the babies must have been able to fledge.

Carolina wren P5181745© Maria de Bruyn res

Many birds will use both tree cavities and nest boxes, depending on what is most convenient or available. Sometimes, they make their own new nest holes in snags, like this red-headed woodpecker (Melanerpes erythrocephalus).

red-headed woodpecker 2G0A0033© Maria de Bruyn res    red-headed woodpecker 2G0A0248© Maria de Bruyn res

Northern flicker P4217370© Maria de Bruyn res

This Northern flicker (Colaptes auratus) was very busy working on a new cavity as well. I followed her and her mate for some time but was never able to see them feeding nestlings as our area had several weeks of hard rain and the nearby lake flooded. I didn’t feel like wading through the lake to get to the snag to check up on them, even after the water had receded a bit.

Brown-headed nuthatches (Sitta pusilla) chose a snag that was usually in the water at the edge of Jordan Lake. The hole faced out into the lake so the fledglings were going to have to fly out and veer left or right immediately in order to get to a resting place!

brown-headed nuthatch P4175229 © Maria de Bruyn res

Eastern bluebirds (Sialia sialis) will use nest holes built by themselves or other birds in previous years.

Eastern bluebird P4070231© Maria de Bruyn res

Eastern bluebird P7070899© Maria de Bruyn resThis year, the Eastern bluebird pair who frequent my yard chose not to use their usually preferred nest box. I believe it’s because they could see me watching them and they don’t like that at all! If they see me with my camera, it doesn’t stop them from flying up to the feeder or sitting on a branch near the porch. If I point the camera toward the nest box, however, they stare at me in dismay, remain on branches near the box, and refuse to go in until I shift the camera away. They did come to my feeders multiple times daily to feed their first brood (one of whom is pictured at right), once they had fledged from a nest in someone else’s yard.

Eastern bluebird P7091193 © Maria de Bruyn resTo my surprise, a couple weeks back, the bluebirds chose to use a decorative nest box that I had bought for decoration. It hangs from a pole and sways in the wind and was not really sturdy. The roof began to let loose in the middle and the décor was curling up from the exposure to rain. But when I finally looked in the box when the parents were gone, I found four nestlings inside. They were pretty well grown already and I thought they might be fledging this past week. I didn’t see it, although I did watch a bit. Yesterday, I found one half of the roof on the ground and the nest was empty. I hope that the babies fledged and not that some larger bird plucked them out after the roof came off.

The materials used for nests can differ quite a lot. House wrens (Troglodytes aedon) make loose frameworks of twigs and the nests look pretty messy inside a box.

house wren 2G0A9598© Maria de Bruyn res         house wren P5181711© Maria de Bruyn res

They do seek out some softer materials with which to line the nest.

house wren 2G0A1982 © Maria de Bruyn res

Carolina chickadees (Poecile carolinensis) make beautiful cups of moss and line them with softer materials – plant fluff or hair from mammals that they find.

Carolina chickadee P3285249 © Maria de Bruyn res     Carolina chickadee IMG_8789© Maria de Bruyn res

Cliff swallows (Petrochelidon pyrrhonota) use mud to construct nests, often underneath bridges and rafters in more urban areas.

cliff swallow 2G0A3239© Maria de Bruyn res     cliff swallow 084A3656 © Maria de Bruyn sgd res

It is well-known that hummingbirds use spider web to help hold their nests together. Blue-gray gnatcatchers (Polioptila caerulea) are also known for doing this.

blue-gray gnatcatcher IMG_8085© Maria de Bruyn res

blue-gray gnatcatcher P4027629 © Maria de Bruyn res

I was surprised a couple years ago to find a nest-building Northern parula (Setophaga americana) also collecting spider web – it appears to be a popular construction material for the birds!

Northern parula 2G0A6727© Maria de Bruyn res

I will leave you with a couple photos from one of my favorite types of nests – that of the white-eyed vireo (Vireo griseus). The first time I saw one being built, I was quite surprised as the birds had chosen a low sapling only about 2 feet from a pathway. They weren’t fond of me watching so I took some photos and left. When I returned some days later, they had completed the nest. (The one below is a different bird.)

white-eyed vireo 2G0A5756© Maria de Bruyn res2

The nests are obviously well-made. This year, I came across an empty nest – also in a low shrub right next to a walking path. It has withstood strong winds, heavy rainstorms and other weather. Now it is a lovely decoration for walkers to see as they pass by.

white-eyed vireo P6125921© Maria de Bruyn res

Next up in the blog series: raising babies!

Some previous blogs about nesting can be seen here and here.

The birdy breeding cycle 2020 – 1: courtship and mating

Although we in the Northern hemisphere are already a little more than a month into summer, many species among our avian friends have not yet completed their breeding cycle. In my yard, many parents are still feeding begging (sometimes almost adult) children. Others are feeding young ones in the nest and some appear to be busy constructing new nests for a second or third brood. So, after a long hiatus in blogging, I decided to feature some of my bird friends, including the American goldfinch pair below (Spinus tristis) as they have worked on their new family lives in 2020.

American goldfinch P7130178 © Maria de Bruyn resSome of these photos go back to early spring. A series of misfortunes (including a crash of my laptop hard drive, a broken camera, loss of Internet) meant that I had a backlog of photos to process and then suddenly a large gap in photos taken. But I managed to recuperate some of the work and hope you enjoy the coming series of posts about the birds’ breeding and family life!

belted kingfisher

Breeding season is heralded by increasing bird song in the meadows, forests, fields and our yards. Males especially sing to attract mates and establish territories, but females treat us to songs and calls, too. This makes it easier to spot birds as the tree foliage gets thicker, especially if you have good hearing!

pine warbler P4175086© Maria de Bruyn                     white-eyed vireo P4123164 © Maria de Bruyn res

Pine warbler (Setophaga pinus)            White-eyed vireo (Vireo griseus)

Eastern meadowlark P4279816© Maria de Bruyn res            Orchard oriole P4279889© Maria de Bruyn res

Eastern meadowlark (Sturnella magna)     Orchard oriole (Icterus spurius)

Carolina wren P3316544 © Maria de Bruyn res                 blue grosbeak P4291500© Maria de Bruyn res

Carolina wren (Thryothorus ludovicianus)      Blue grosbeak (Passerina caerulea)

summer tanager P4291520© Maria de Bruyn res

Summer tanager (Piranga rubra)

Indigo bunting P6308502© Maria de Bruyn

Indigo bunting (Passerina cyanea)

Courtship is usually a sweet behavior to watch in my view. The male Northern cardinals (Cardinalis cardinalis) are especially devoted suitors, seeking out nice morsels to present to their intended mates, while among the American crows (Corvus brachyrhynchos), it’s the females who loudly call to their mates for some tasty bites.

Northern cardinal P4164873© Maria de Bruyn res

American crow P4080661 © Maria de Bruyn res

A fact that perhaps many bird lovers do not know is that few male birds have a penis. Like the female birds, most species’ males have a cloaca, a cavity externally located just under the bird’s tail and internally at the end of the digestive tract. Feces, urine, sperm and ova are all deposited in the cloaca. Birds who reproduce with this organ briefly rub their cloacae together (an activity called the “cloacal kiss”) whereby sperm from the male bird’s testes are transferred into the female’s cavity to unite with her eggs. During breeding season, the cloaca is slightly swollen and protrudes a bit from the bird’s body, facilitating the transfer. In the photo of this Carolina wren, you can see a slightly darker area under the tail indicating where the cloaca is found.

Carolina wren P7059955 © Maria de Bruyn res

red-headed woodpecker P4217162© Maria de Bruyn res

When ready for mating, the red-headed woodpeckers (Melanerpes erythrocephalus) seem to focus mainly on chasing away rivals and then snatching a quick mating session. The female woodpecker then takes a break from the chase to rest and have a bite to eat.

Some cliff swallow males (Petrochelidon pyrrhonota) seem to take advantage of females who are preoccupied with gathering mud for their nests for a quick tryst.

cliff swallows 2G0A3283© Maria de Bruyn res

The brown-headed cowbirds (Molothrus ater) seem to take their time for mating. This pair was occupied for at least 5-10 minutes in preparing for the upcoming production of eggs. At times, it seemed like the male was giving the female instructions on what to do once “the deed” was done!

brown-headed cowbird P5097676 © Maria de Bruyn res   brown-headed cowbird P5097677 © Maria de Bruyn res

Many birders do not like the cowbirds because they are parasitic nesters, i.e., they lay an egg in another bird’s nest so that the other bird will raise the young. Since the cowbird baby usually hatches before the other eggs, they either monopolize the food that the foster parents bring or they may even destroy the eggs laid by their foster mother.

brown-headed cowbird P5097682 © Maria de Bruyn res      brown-headed cowbird P5097686© Maria de Bruyn res

It’s been posited that the cowbirds evolved to use this strategy because they followed the bison in migration and therefore couldn’t stay in one place to raise their young. Others believe, however, that the birds developed the practice because dispersing their eggs over several nests gave their young a better chance of reaching adulthood.

brown-headed cowbird P5097689© Maria de Bruyn res

chipping sparrow P6256620© Maria de Bruyn sgd resThe quickest mating scenario I’ve witnessed came from a pair of sweet little chipping sparrows (Spizella passerina). I’d seen the two fluttering together at the feeders and had noted one sparrow chasing another away – which I now think was the victorious suitor driving away a rival. Then one July afternoon, the two flew to a dying cedar and sat close to one another on a branch. Suddenly, Mr. Victory mounted his mate but for what only seemed a few seconds – really very quick work indeed! She sat there with her rear end elevated for a bit and then the two went back to feeding – and soon after I saw them collecting nesting materials.

chipping sparrow P6256622© Maria de Bruyn res    chipping sparrow P6256623© Maria de Bruyn res

The birds in which the males do have a penis include some duck and swan species, ostriches, cassowaries, kiwi and geese. They differ from other birds in that development of the penis is NOT stopped in the male bird embryos during development (the case in cloacal birds).

The mallard males (Anas platyrhynchos), like some other ducks, unfortunately do not treat their partners well. They may mount the female very roughly. During a mating, she may be dunked underwater repeatedly and at length; occasionally, this results in her drowning. This behavior has been the subject of various studies and some newspaper articles with sensationalistic headlines (e.g., “The horrible thing you never knew about ducks)”.

Mallard duck P1232837 © Maria de Bruyn

Mallard duck P1232839 © Maria de Bruyn     Mallard duck P1232840© Maria de Bruyn

Once the actual mating is over, the birds devote most of their energy toward building a nest. While female ruby-throated hummingbirds (Archilochus colubris) must construct her nest and tend her babies alone, many other birds cooperate in the venture, like the Eastern bluebirds. Their efforts are featured in the next blog. (And if you’d like to see a previous post on courtship, it is here.)

ruby-throated hummingbird 2G0A4084© Maria de Bruyn res