Avian generations in the making – part 3A: raising and feeding babies

So here in North America, it’s approaching winter and it may seem a bit weird to have another blog at this time on birds raising their young. But I wanted to complete the series even though it has been delayed because of my volunteer activities and commitments the past month. Also, it is now late spring in the Southern hemisphere so for some people this is seasonal and there are other birds around them that are getting ready for babies, though different species than these American robins (Turdus migratorius). Because this part kept growing longer as I worked on it, I’ve divided it into two parts – this one on raising the babies until fledging and the next one on fledging and post-fledgling care. I hope all of you who read this will enjoy it no matter where you live.

It’s fascinating to me to watch the birds during their reproductive cycle; I always learn something new. Once parent birds have completed a nest to their liking, the female lays her eggs and proceeds to brood them, with some species sitting on the eggs almost full time right away and others taking breaks.

           

Carolina wren (Thryothorus ludovicianus)              Eastern bluebird (Sialia sialis)

An acquaintance recently told me about a friend of hers who commented that she had seen a very pregnant goose that was so fat, she was waddling. The acquaintance proceeded to give an avian reproduction lesson to her friend – a woman in her 80s – who apparently did not know all birds lay eggs! Even after babies hatch, the Canada goose (Branta canadensis) may still look well-fed!

Some bird species have young who are “precocial”, that is, they are covered with downy feathers and have open eyes when they hatch and are soon able to feed themselves. These species include turkeys and ducks, like these mallards (Anas platyrhynchos), and the young often leave the nest soon after birth (which makes them “nidifugous” – good Scrabble word!). The newborns may look fuzzy but it’s not long before they start to take after their parents’ looks.

Other birds, such as songbirds, are altricial (as are human beings) – they are naked and helpless at birth and require considerable care before they can walk, fly and feed themselves. If you have some in a nest that is easily observable (and you can take photos when parents are not there so you don’t distress them), it’s interesting to see how the babies develop.

               

Carolina chickadees (Poecile carolinensis) on 18 and 22 April           

Brown-headed nuthatches (Sitta pusilla) on 13, 25 and 29 April

 

 

Eastern bluebirds (below)

     

As the mother incubates the eggs, her mate will often feed her so she doesn’t have to leave the nest. This young osprey (Pandion haliaetus) was assiduous in bringing his female life companion fish. Then as the babies hatch, in many species both the male and female parents get busy bringing the young frequent meals.  It’s estimated that Carolina chickadees, for example, will bring over 5000 insects to their brood before fledging!

Northern mockingbird (Mimus polyglottos)

     

House finch (Haemorhous mexicanus)  and Red-headed woodpecker                (Melanerpes erythrocephalus)

              

Orchard oriole (Icterus spurius)                  Blue grosbeak (Passerina caerulea

  

Eastern phoebe (Sayornis phoebe)

In some species, the previous year’s young will help their parents with the new brood. Brown-headed nuthatches and American crows are examples of this. A pair of Canada geese that I observed this past spring seemed to have a domestic goose helping them out.

The parents have other chores, too. They must keep the babies safe from predators – Both American crows (Corvus brachyrhynchos) and common grackles (Quiscalus quiscula) will be chased away by songbirds, for example, because these birds will raid nests to eat eggs and babies. But the grackles must also protect their own young against the crows, pursuing them non-stop to drive them away.

 

For other birds, protecting the young can be more difficult. This mother wood duck (Aix sponsa) was raising her brood in a pond that was home to at least three large snapping turtles (Chelydra serpentina). Ultimately, another birder and I thought she only had two ducklings survive.   

Keeping the nest reasonably clean is another chore. The babies make this task a little easier than you might think because they defecate into a mucous membrane that forms a sac. When you watch a nest box, especially when it gets closer to fledging time, you can periodically see the parents flying out of the box with a white blob in their mouth, which turns out to be a fecal sac. They either discard it elsewhere or sometimes eat it for some nutritional benefit.

        

Brown-headed nuthatches

This year, I was surprised to have caught a female blue grosbeak during the cleaning – it appeared that she was actually pulling the fecal sac from the baby! Later, I read that some species stimulate defecation by prodding the babies’ cloaca so they can get on with the chore. I also caught a photo in which a baby bluebird had just presented its rear end to the parent for removal of a sac. I could imagine that some human parents might think a fecal sac would be a cool avian adaptation for their babies to have – no more dirty diapers and expense for diapers either! (An idea for an SF short story?)

     

 

After all their efforts, the parents are usually ready for those babies to fledge – the subject of the upcoming last blog in the series.

 

 

* Not all the photos in this blog are of great quality, I know, but my intention was first to show behaviors and secondarily to have some nice shots in the blog.

 

 

Leaping into the wide – and sometimes wet – world!

Eastern bluebird IMG_2991© Maria de Bruyn resEarlier this past week, I calculated that the Eastern bluebird (Sialia sialis) babies in my front-yard nest box were close to fledging. I knew approximately when mom had finished laying her eggs (four in total), so that I could guess when they reached normal fledging age (16-18 days after hatching). When I looked at the nest on 10 June, I saw that there were only three babies; I have no clue what happened to egg No. 4.  But the three survivors were progressing well as mom and dad made frequent forays to gather caterpillars and insects for them.

Eastern bluebird IMG_2819© Maria de Bruyn res Eastern bluebird I77A5733© Maria de Bruyn res

Eastern bluebird I77A8417© Maria de Bruyn

Occasionally, the male and also the female bluebird, identifiable by her subtler coloring and her brood patch, would visit the suet and meal worm feeders for a fast food repast for themselves. It was hard work keeping their growing offspring fed!

Eastern bluebird I77A6411 © Maria de Bruyn         Eastern bluebird I77A5769© Maria de Bruyn

They also had to let one of their older offspring from a previous brood know that they were no longer going to feed him, even when he begged.

Eastern bluebird IMG_1509© Maria de Bruyn res

As fledging time neared, mom and dad had to contend with other birds coming near the box. Dad was especially angry with a young starling (Sturnus vulgaris) who wanted to settle on top of the box. Starlings have been known to eat young birds and papa bluebird was obviously taking no chances! (I just caught the action out of the corner of my eye so the photos aren’t great but do give an idea of the argument!). The parents also chased away squirrels from the tree in front of the box, which alerted me to the fact that fledging was probably imminent since the parents become especially protective at this time. I started using a smaller camera with a very long zoom (but somewhat lesser photo quality) as they weren’t excited by me being too close either.

Eastern bluebird IMG_3841© Maria de Bruyn res     Eastern bluebird IMG_3840© Maria de Bruyn res

Eastern bluebird IMG_4618© Maria de Bruyn res

On Wednesday, I checked the box before going out for the morning and there were still three babies there. When I came home a few hours later, mama and papa were sitting on branches, with or without food, calling to their little ones to come on out. They would also fly to the box for a quick look inside.

Eastern bluebird I77A7702© Maria de Bruyn res           Eastern bluebird I77A7729 © Maria de Bruyn res

Mama also repeated behavior I had seen last year – flying to the box, standing on top and then hovering in front of the hole as a form of encouragement.  When she and dad left, I approached to take a look and discovered bluebird baby No. 1 had already flown away. This meant that the parents had to watch the first baby out in the trees somewhere, as well as their two lagging offspring in the box.

Eastern bluebird I77A8584© Maria de Bruyn res        Eastern bluebird I77A8791© Maria de Bruyn res

Eastern bluebird I77A8592© Maria de BruynAt one point, mother bluebird seemed a bit fed up – she flew over to the box (without food) and finally entered, staying inside for a good 60-90 seconds at least. I imagined her giving the babies a lecture about how they had to be courageous and willing to jump.

Her admonishments seemed to have had an effect; the babies began calling loudly from inside their birth home. Finally, after about 30 minutes, one poked its head out to take a look at the big wide world. Mom and dad seemed glad, waiting together in the tree to see how long it would take baby No. 2 to join them.

Eastern bluebird I77A8685© Maria de Bruyn    Eastern bluebird I77A8648© Maria de Bruyn

The baby looked around a lot, also staring at me; s/he went back inside and then looked out a few more times, finally taking the great leap into the outside world. Baby 2 was a very strong flier – not even alighting in the tree in front of the box but circling around to land high in a juniper and then in a tall oak tree behind the box.

Eastern bluebird I77A8746© Maria de Bruyn res

Eastern bluebird I77A8877© Maria de Bruyn res

 

Sibling No. 3 took a little while longer and mama bluebird again went to the box to give encouragement. The baby then spent a little more time observing the new environment and also made a strong flight out.

Eastern bluebird I77A8899© Maria de Bruyn res Eastern bluebird I77A8891© Maria de Bruyn res

Eastern bluebird I77A8861© Maria de Bruyn res  Eastern bluebird I77A8925© Maria de Bruyn

Eastern bluebird I77A8930© Maria de Bruyn res Eastern bluebird I77A8931© Maria de Bruyn     Eastern bluebird I77A8932© Maria de Bruyn res

It rained that night and I hoped that the bluebird babies were ok; between the thunderstorms and a neighbor’s cat who comes to hunt birds in my yard, their environment seemed precarious for their first days of life. In the afternoon, I was happy to see papa bluebird feeding one of the three babies at the top of an oak tree. Mama was also flying around up there, so I assumed they were all hanging out in the high branches.

Eastern bluebird IMG_4723© Maria de Bruyn        Eastern bluebird IMG_4777© Maria de Bruyn res

Thursday night, it rained heavily again for many hours; Friday was an easier day and night. I haven’t seen the fledglings again yet but have seen their parents coming for suet and meal worms and flying up to the oak tree, so I assume at least a couple are there. I look forward to seeing their speckled selves at the feeders along with their parents – and will be curious to see if their parents go for a third brood this year.

Eastern bluebird IMG_4779© Maria de Bruyn res

 

Communal nesting – the rookery at Sandy Creek Park

great blue heron DK7A5496© Maria de BruynUnlike Eastern bluebirds (Sialia sialis) and other songbirds, great blue herons (Ardea herodias) like to build their nests near one another, forming what is called a rookery, or colony of nests. The nests are often seen in the tops of tall trees and comprise large twigs and branches that surround grass, leaves and moss. As many as 135 nests have been counted in a rookery, but the one at Sandy Creek Park that I visited this spring had three nests.

The herons return to the nests for several years running. Each year, the males re-furbish the nests in order to attract a mate.

great blue heron DK7A7297©Maria de Bruyn great blue heron DK7A7367©Maria de Bruyn

You can see the nests well with binoculars from a walking path, but as I have no binoculars and rely on my camera’s zoom lens, I slogged through forest and marshy terrain on numerous occasions to get close to the pond that had their rookery pine trees on the other side. They were still a bit out of range for my lens, but occasionally I managed to get a half-way decent shot, which encouraged me to return often to follow the nestlings’ progress.I followed them from 8 March through 26 June.

great blue heron DK7A5924© Maria de BruynGreat blue heron DK7A3689© Maria de BruynThe top nest in an open-to-the sky tree appeared to have four babies, while the nest below it had three.

A nest in a tree to the right, which had much more dense foliage, seemed to be occupied by only one or two babies.

great blue heron DK7A6005© Maria de Bruyn

There were always 1-4 adults around, including both parents on the nest and “guards”, who took up posts atop nearby trees to watch the nearby skies. This is one reason for the rookeries; the herons want to ensure that there are adults around to protect the nestlings from predators, which include raccoons, crows and hawks, such as this red-shouldered hawk (Buteo lineatus) that was hanging around the nests one day.

red-shouldered hawk DK7A7354© Maria de Bruyn red-shouldered hawk DK7A7371© Maria de Bruyn

great blue heron DK7A6601© Maria de BruynGreat blue heron DK7A3495© Maria de Bruyngreat blue heron DK7A8238© Maria de Bruyn resThe parents feed their young by regurgitating food and the young birds get excited when a parent returns after being away for a time.

The nestlings make quite a lot of noise squawking loudly while they jostle to get first in line for the meal.

great blue heron DK7A3743© Maria de BruynThe young herons appear to “argue” with one another with loud calls and it seemed that they “jousted” with one another using their beaks.

great blue heron DK7A3735© Maria de Bruyn

Weaker chicks may miss out on getting enough food and can die of starvation, but that didn’t happen at the Sandy Creek rookery. Some chicks were obviously larger and stronger than others, but even the smallest fledglings survived.As they grew, the babies began standing tall and walking around the nest.

great blue heron DK7A8283© Maria de Bruyn Great blue heron DK7A3638© Maria de Bruyn

great blue heron DK7A9348© Maria de BruynWhen they were close to fledging, they stood near the edge of the nest and practiced spreading and flapping their wings. Sixty days after hatching (much longer than smaller birds!), the young herons were ready to fly and began taking short flights to nearby trees, before venturing out on farther trips. great blue heron DK7A8960©Maria de BruynThe young ones will not breed until they are two years old.

Watching events unfold at the rookery was a new past-time for me this year and likely one I’ll repeat in the future. If you have time and the opportunity, I’d recommend the experience!

New bird generations emerge in my yard!

This spring and summer, I’ve had the pleasure of watching various species of birds in my yard care for new offspring until they have fledged (left the nest). My most recent observations came today as I watched three hatchlings jump bravely into their wide new world. This blog will introduce you to some of my new neighbors; two blogs to follow will go back in time to spring and early summer to describe some nesting I witnessed in local parks and reserves.

gray catbird IMG_3888© Maria de BruynA dense privet tree next to my carport offered a pair of gray catbirds (Dumetella carolinensis) space to construct a well-hidden nest. I discovered it was there because the parents suddenly began yelling at me loudly whenever I left the carport to walk into the yard and then a bird bander who was visiting managed to locate the nest, which was about 8 feet up so I couldn’t see the eggs in it.

I kept an eye on the shrub and saw the parents were flying in with insects and emerging empty-beaked, so I knew the eggs had hatched. One day, I ventured close and peered through the privet branches and saw a couple little heads sticking up above the nest.

gray catbird IMG_3933© Maria de Bruyn res gray catbird IMG_3903© Maria de Bruyn res

A short time later, the baby birds hopped out of the nest and they stayed in the large shrub for several days as their parents continued bringing them a variety of insects.  As I mentioned in a previous blog, the parents were good providers, sometimes bringing more than one type of insect home in their beaks.

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

Eastern bluebird IMG_3881© Maria de Bruyn resA pair of Eastern bluebirds (Sialia sialis) laid five eggs in a nest box in my front yard and I was able to record when all the eggs had been laid. Information provided online about time to hatching (12 to 14 days) alerted me as to when I might see newborns.  Only four of the five eggs hatched; the fifth one was broken. I also checked how long it takes for hatchlings to develop until they leave the nest – that can take 16-21 days but usually 17-18 days.

Eastern bluebird DK7A3842© Maria de Bruyn res

 

The bluebird parents were diligent about bringing food, mostly caterpillars and insects but supplemented by wild raspberries and dried meal worms that I had made available. It turned out this brood wasn’t too interested in the meal worms; I found a layer of them in the nest when the babies fledged.

 

Eastern bluebird DK7A3411© Maria de Bruyn resEastern bluebird DK7A8706© Maria de Bruyn res

 

Eastern bluebird DK7A3210© Maria de Bruyn resEastern bluebird DK7A8685© Maria de Bruyn res

Eastern bluebird DK7A3137© Maria de Bruyn RESClose to fledging, the parents began showing protective behavior – chasing squirrels out of the large tree in front of the nest box, flying at other birds that came too close, keeping an eye on me as I sat near the box. Mama and papa removed fecal sacs frequently, flying off with them to a considerable distance from the nest. Only once did I see a parent actually swallow the fecal sac.

 

Eastern bluebird DK7A3081© Maria de Bruyn resMama investigated something odd at the edge of the box one day, flying down to look closely at the gap between the box wall and door. When I looked, I didn’t see anything. She also would occasionally hover in front of the nest box opening, as if she was demonstrating to the babies what they had to do.

Eastern bluebird DK7A3149© Maria de Bruyn res Eastern bluebird DK7A3174© Maria de Bruyn res

I was lucky enough to see all four babies leave the nest. Two of them were definitely stronger than the other two, who couldn’t fly as well and who didn’t seem to have feathers that were so well developed. When I moved close to take photos, the cautious parents dive-bombed me and the young eventually moved across the street. I never saw the young ones at my feeders.

Eastern bluebird DK7A4306© Maria de Bruyn resEastern bluebird DK7A4281© Maria de Bruyn res

Eastern bluebird DK7A4489© Maria de Bruyn res Eastern bluebird DK7A4386© Maria de Bruyn res

These past few weeks, some bluebirds raised a second brood in my backyard. This nest had some history. First, three eggs were laid, with a pair of bluebirds visiting the nest occasionally. Unfortunately, one day I saw a Cooper’s hawk (Accipiter cooperii) swoop in and it looked like the raptor had caught one of the bluebirds. In any event, the eggs were abandoned. After a few weeks, I had just decided to clean out the nest with eggs when I suddenly saw another pair of bluebirds building a new nest on top of the old one. They, Eastern bluebird DK7A7145© Maria de Bruyn restoo, laid three eggs.

Using the guidance given to me by the Smithsonian Institute’s Backyard Nestwatch Project, I checked the box every three days until the eggs hatched and then every two days to check on the nestlings’ well-being.

I was surprised that the mother was not sitting on the eggs much of the time, but the local Audubon chapter president told me that when the weather is very hot, the parent will not brood because it could become too warm inside the box.

The parents were quite diligent in bringing food to the hungry babies. They occasionally visited my mealworm and suet feeders but mostly just to feed themselves. They appeared to be feeding their babies an exclusive diet of caterpillars and insects and a little bit of suet – no mealworms though.

Eastern bluebird DK7A7038© Maria de Bruyn resEastern bluebird DK7A8265© Maria de Bruyn res

Eastern bluebird DK7A8265© Maria de Bruyn res Eastern bluebird DK7A8041© Maria de Bruyn res

They were busy removing fecal sacs as well and I discovered that the baby birds actually present the sac to the parent by sticking up their behinds so the parent can pull out the sac. That made for a couple unusual photos!

Eastern bluebird DK7A8089© Maria de BruynEastern bluebird DK7A8106© Maria de Bruyn res

 

Eastern bluebird DK7A8351© Maria de Bruyn res

Eastern bluebird DK7A8316© Maria de Bruyn resI had calculated that today or tomorrow would likely be fledging day so after a doctor’s appointment and grocery shopping, I settled into a canopy chair to observe the box. The parents were very busy bringing food but also taking time to sit in the crepe myrtle tree across from the box to call to their little ones. The nestlings were now sticking their heads out of the box so I figured that fledging was imminent.

As I watched the parents and nestlings for an hour, I also looked around at the other bird activity in the yard. Suddenly, I saw an immature red-bellied woodpecker (Melanerpes carolinus) take interest in the nestlings and it swooped over to the box. I feared for the little ones but one of the parents descended on the larger bird to drive it away from their temporary home.

red-bellied woodpecker DK7A8468© Maria de Bruyn resred-bellied woodpecker DK7A8472© Maria de Bruyn res

Eastern bluebird DK7A8532© Maria de BruynAfter a while, I thought bird No. 1 was going to jump but at the last minute s/he crawled back inside. I was occasionally turning my head to observe other birds at feeders and just as I turned my head again, action erupted.

Eastern bluebird DK7A8660© Maria de Bruyn resI was warned because the bluebird parents swooped down from the crepe myrtle tree to fly straight at my head under the canopy of my chair – they were not taking any chances! It turned out that bird No. 1 had flown by me and landed on the side of my screened-in porch, which was where I had been looking.

Eastern bluebird DK7A8714© Maria de BruynEastern bluebird DK7A8715© Maria de Bruyn res

The parents continued to fly at me, perhaps 6 or 7 times coming very close to my face, so I went on the porch so that they could calm down. Then they began chasing other birds as their young one had flown from the porch to a tree. While they were occupied, I went back to the chair and was able to see babies 2 and 3 jump from the nest box.

Eastern bluebird DK7A8864© Maria de Bruyn resEastern bluebird DK7A8865© Maria de Bruyn res

Eastern bluebird DK7A9056© Maria de Bruyn resEastern bluebird DK7A9058© Maria de Bruyn res

Eastern bluebird DK7A9059© Maria de Bruyn res

It was a partly cloudy, partly sunny morning for the fledging today and then a few hours after the bluebird young flew, the rain began. There has only been a little thunder and no lightning so perhaps this will just be a nice steady rain that we can use and not severe weather. I do feel a little sorry for the new members of our local bluebird society, however, as they have to face getting sodden on their first day outdoors. The parents are visiting the mealworm feeder now; I hope I get to see the babies at my feeders the coming days. In any event, they made my morning very enjoyable indeed and I have a third nesting report to add to Backyard Nestwatch!

 

P.S. I have higher-resolution photos for sale as prints or photo cards; let me know if you ever want a particular one!