Growing up barred – Part 3: Strife and affection

In the nest, baby barred owls (Strix varia) are vulnerable to predators including hawks, weasels, raccoons and other owls. When they are out on their own and already able to fly, they eventually have less to fear. Their main predator becomes the one owl larger than they are in North Carolina, the great horned owl.

As pointed out in the previous blog, however, they can be fearsome predators to many other species of animals including songbirds, woodpeckers and other avian species. On a few occasions, I noticed the young owls at the Mason Farm Biological Reserve gazing about with expressions that seemed to express wonder and confusion.

It turned out that they were being dive-bombed by members of a very small bird species, the blue-gray gnatcatchers (Polioptila caerulea). The owlets seemed to have no interest in pursuing the gnatcatchers, but they were perching in areas where the small birds had had their nests so the little gnatcatchers did their best to drive the owls away.

  

One day, they succeeded. The owls flew to the other side of a path through a bog. One landed on a branch right over my head and looked down at me with what I imagined was an expression of “Hey, what did I do???”

The young owls were very affectionate with one another. They often perched next to or near one another.

 

They often sat close together, expressing what looked to me like affection.

 

 

When they were apart, they would vocalize. It would have been cool to be privy to the meaning of their communications.

 

The young birds seemed to enjoy nuzzling and grooming each other.

 

  

When I stopped seeing the young owls in their usual haunts, I figured the time had come for them to separate and seek out a mate and new territory. Mated owls usually establish nests about 400 yards away from other barred owls although some nests have been observed as close as 100 to 200 yards apart. The young owls may not have flown very far away but they did need to leave their parents’ area. I hope they made it and was happy to have had the opportunity to watch them mature. My next goal for owls – to see a species in the wild that I have not yet seen (e.g., great grey owl, screech owl, barn owl, etc.). I hope you, too, have the chance to see members of this avian group up close!

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.

 

 

Avian generations in the making – part 2A: nesting and man-made construction

Hi folks — today I’d like to share with you some of my observations on the second part of avian reproduction — the process in which birds make a nest and lay eggs. (By the way, if you look up “bird nesting” on the Internet, the search will lead you to a human activity: a shared custody arrangement where children reside in one house and the parents take turns living there with them. In the bird world, some avian parents will actually share a home, such as this very old and enormous sociable weaver nest (Philetairus socius) that I saw in Namibia.)

Females of a few species will deposit their eggs in the nests of another, such as some cuckoos and brown-headed cowbirds (Molothrus ater). Some people dislike cowbirds intensely because of their nest parasitism (the cowbird baby will hatch first and eat all the food or perhaps get rid of the other eggs or babies). I figure that this is how the cowbird evolved – it didn’t make a choice to wipe out other species so I can’t blame or hate the bird for it. But the cowbirds do appear to pick on particular species as involuntary “foster parents” and this may be affecting the success of the other species’ reproduction.

There are two general broad categories of bird nests – those located in or on man-made objects such as nest boxes, atop downspouts, in vehicles, in plant pots and other places and those constructed by birds in trees, shrubs and on the ground (i.e., the natural environment which I will discuss in the next blog so this doesn’t get too long!). When birds make a nest in a “human area”, people will often try to accommodate them, not using the object or vehicle or making the space safer. For example, when American robins (Turdus migratorius) put a nest on one of my downspouts, I covered the rainwater container underneath it so the fledglings wouldn’t drown when they leapt to freedom. (I did it just in time, too!)

Swallows and phoebes will also use human constructions as places to situate their homes. The cliff swallows (Petrochelidon pyrrhonota) gather up mud, making countless trips to wad up small balls of the material to carry back to a place like this pier at Cane Creek Reservoir where they line up their nests in a row.

   

Barn swallows (Hirundo rustica) locate their nests inside, using rafters to place a nest; they may end up sharing space with paper wasps and organ pipe mud dauber wasps (Trypoxylon politum), which doesn’t seem to bother them.

The Eastern phoebe (Sayornis phoebe) may use an inside corner of a patio overhang as a site that is conveniently accessible from outside.

Purple martins (Progne subis) living east of the Rocky Mountains almost exclusively nest in homes provided by people. The hanging gourd nests can be seen in fields but nowadays other types of plastic constructions are also used.

    

In order to attract barn owls (Tyto alba) back to areas where many traditional barns have been razed, people are also placing special boxes in fields with plenty of open space in front of them so that the owls will have a hunting territory adjacent to their front door. Made of heavy plastic, these boxes may be monitored by organized groups in an effort to document their use.

   

At the Mason Farm Biological Reserve, an eagle scout project involved bringing in cranes to attach very large nest boxes to the tops of trees for barred owls (Strix varia) – so far, I have only seen Eastern gray squirrels making use of these nests.

And then there are the nest boxes that people put up to attract Eastern bluebirds (Sialia sialis), brown-headed nuthatches (Sitta pusilla) and screech owls. In my yard, other birds use these boxes, too, including the Carolina chickadees (Poecile carolinensis) such as my one-legged,  banded friend Chantal, Carolina wrens (Thryothorus ludovicianus) who may puzzle about how to get a long twig into the box and house wrens (Troglodytes aedon), who pile up twigs in a rather untidy stack inside the box.

   

   

Chickadees construct lovely mossy nests lined with hair, fur or plant fibers.

      

The nuthatches have nests with bark strips.

    

Sometimes people will intervene when a nest is in danger. A Carolina wren put her nest into a boat at Cane Creek Reservoir that was rented out to people and keeping the nest there was not a good option as she would be missing her nest for hours when the boat was gone. The land manager was so kind as to relocate the nest into a tree right in front of the boat’s resting place; unfortunately, inclement weather caused the nest to dislodge that evening.

   

Another danger may also threaten the birds and their nests – predators. A friend and I found it unusual to see a tree swallow (Tachycineta bicolor) putting a nest in a bluebird box on the edges of a farm. Several days later, we saw a black rat snake (Pantherophis obsoletus) peering out of the box and the swallows were nowhere to be seen.

   

If you can manage to mount your boxes on poles rather than trees, put both squirrel and raccoon baffles on them and also place them away from overhanging branches, they should stay relatively safe from the squirrels, snakes and raccoons. Next up: birds’ nests with no human connections.

 

 

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!

A life and death drama on a nature walk

ice DK7A6116©Maria de BruynFrost was sparkling on the grass, dried shrubs and grasses as our small group set out on a birding walk in the local nature preserve. Water in the creeks and bog was frozen in pretty patterns and the air felt crisp (and cold).

 

 

ice DK7A6094©Maria de Bruyn

Eastern towhee DK7A5990©Maria de BruynAt first, not many birds seemed to be aroblue jay DK7A5949©Maria de Bruynund but soon we spotted Eastern towhees (Pipilo erythrophthalmus) and numerous sparrow species in the meadows — none really close by but still visible to those with binoculars and a zoom lens. Blue jays (Cyanocitta cristata) were flying from very high treetop to treetop.

After seeing my familiar red-headed woodpecker (Melanerpes erythrocephalus), to whom I’ve given the name “young’un” as I’ve been following her/his progress since s/he was a brown and white juvenile, we saw some Eastern phoebes (Sayornis phoebe) and more sparrows.

Eastern phoebe DK7A6061©Maria de Bruynred-headed woodpecker DK7A6013©Maria de Bruyn

hairy woodpecker DK7A6163©Maria de BruynIn the woods, we saw a ruby-crowned kinglet and a yellow-bellied sapsucker (Sphyrapicus varius). It was when we emerged from the woods into another meadow that we had our most spectacular encounter, however. I spotted a young red-tailed hawk (Buteo jamaicensis) perched in a tree at the meadow’s edge gazing ahead.

 

 

red-tailed hawk DK7A6229©Maria de Bruyn red-tailed hawk DK7A6245©Maria de Bruyn

red-tailed hawk DK7A6246©Maria de BruynSuddenly, the bird flew across the field (perhaps 150 feet in a fellow birder’s estimate) to land on a branch in a tree right next to our walking path.

red-tailed hawk DK7A6397©Maria de Bruyn res

After alighting, the bird began staring downwards very intently. We walked a little closer and stopped. The bird didn’t even look in our direction but continued to stare down with great concentration, occasionally looking out ahead.

red-tailed hawk DK7A6380©Maria de Bruyn res red-tailed hawk DK7A6370©Maria de Bruyn res

We came closer and stopped again. Finally, we got right up even with the bird and looked directly at it from about 6-10 feet. It acknowledged our presence but continued to stare down and we couldn’t figure out what it was tracking. Other birds fluttered in nearby branches but it paid them no mind.

red-tailed hawk DK7A6411©Maria de Bruyn red-tailed hawk DK7A6414©Maria de Bruyn

red-tailed hawk DK7A6425©Maria de Bruyn red-tailed hawk DK7A6432©Maria de Bruyn res

When our group began to walk on after taking many photos and admiring the bird’s sharp eyes and even sharper looking talons, I looked intently under the tree, too. And then I spotted the prey — a hispid cotton rat (Sigmodon hispidus), holding still as a statue on a log.

hispid cotton rat DK7A6463©Maria de Bruyn res hispid cotton rat DK7A6449©Maria de Bruyn res

The hawk looked at us, yet kept the rodent in sight. On looking at the photos afterwards, I’m glad that the hawk didn’t decide to fly at us with those talons extended in order to drive us away. After looking at the rat, our group walked on as it looked to be quite a standoff; the rat had several smaller branches between it and the hawk which might make capture difficult.

red-tailed hawk DK7A6509©Maria de Bruyn resred-tailed hawk DK7A6488©Maria de Bruyn res

As my fellow birders tried to spot winter wrens and purple finches, which they had heard, I couldn’t get the hawk and rat out of my mind. So as they went on, I returned to the dramatic scene. As I arrived, the hawk had risen on the branch and was crouching as it looked at me and the rat. It turned on the branch and I just knew that it was getting ready for an attack. Part of me wanted the rat to make it out of there and part of me felt the hawk deserved a meal after such stellar spotting from a distance and patience in watching the prey.

red-tailed hawk DK7A6496©Maria de Bruyn resThe hawk looked at me, crouched again and then dropped down with great fluttering of wings.

red-tailed hawk DK7A6525©Maria de Bruyn red-tailed hawk DK7A6531©Maria de Bruyn res

red-tailed hawk DK7A6532©Maria de Bruyn res red--tailed hawk DK7A6548©Maria de Bruyn res

Those large wings were somewhat caught up in the small branches but it got the rat. It flapped about, perhaps securing a tighter hold on its meal-to-be and then flew up to a nearby branch (behind lots of vegetation so that I couldn’t get a good photo). It sat for a minute or so and then flew back over the meadow into the woods, leaving me with a few blurry photos as testaments of the final act in the drama.

red-tailed hawk DK7A6574©Maria de Bruyn res red-tailed hawk DK7A6585©Maria de Bruyn res

red-tailed hawk DK7A6599©Maria de Bruyn resMy sympathy was certainly with the rat, whose last 30 minutes of life must have been filled with terror as it froze in the hope of escaping the predator. I had to admire the hawk’s concentration and focus, though — that bird was not going to let anything deter it from getting a meal, not even four humans standing a few feet away aiming cameras and phones at it as it perched on that branch. The hawk certainly gave us an unforgettable experience as we may never come so closely eye-to-eye with a wild raptor again.

If you liked this post and/or the photos, could you please “like” it so that I know people enjoyed this posting? Thanks in advance!