An avian buffet appears!

In the town where I live, there is a private lake in a neighborhood of single-family homes. The little body of water was created by developers who dammed a local creek; now a neighborhood association levies annual fees for use of the lake for swimming, fishing and boating. In the past month, the neighborhood residents were surprised by an influx of birds that they do not usually see and some photos of the new avian visitors began circulating.

Given my interest in wildlife and birds, some colleagues passed on a couple of photos to me and one couple kindly invited me to come visit so that I could see the new arrivals in person. They were especially curious about the identity of a few ducks. When I arrived, no ducks were in sight, but at least 80 double-crested cormorants (Phalacrocorax auratus) were hanging out in crowds on two floating docks.

Their tightly-packed presence had displaced the Canada geese (Branta canadensis), who are more common lake residents. A group of 11 geese were off in the distance on shore leaving the open water to the visiting avian groups.

Some of the cormorants couldn’t fit onto the platforms, so they swam around in the company of the many dozens of ring-billed gulls (Larus delawarensis) of all ages who were swarming the waters as well.

From time to time, the gulls would begin edging their way onto the platforms, eventually taking up space vacated by the cormorants. There are both adult and immature gulls in the crowd.

From time to time, the gulls launch themselves into the air for aerial forays which end in dives down to pick up a fish, of which there still seem to be plenty. This is because the shad population with which the lake was apparently stocked is dying off as a whole.

Why is this happening? I don’t know the species of shad with which the lake was stocked, but it appears that threadfin shad (Dorosoma petenense) are common in the Southeastern USA and often introduced as forage fish for the bass and catfish that fisher-people seek. The shad are very sensitive to changes in water temperature; when it goes below about 42° F (5.5° C), they expire. In the past 6 weeks, we had an unusual early winter storm with about 8-11 inches of snow, followed by days and days of cold rains. Sometimes, it is cold 24 hours long; other days have nights and dawns below freezing and then afternoon temperatures of 50-60° F (10-17° C). The shad die-off is a result.

  

The newly arrived birds are obviously enjoying the easy pickings. When the gulls drop down to snatch a fish, they are almost always pursued by other gulls who try to make them drop the prize.

 

Even when they alight with a fish firmly held in their beaks, other gulls harass them in an attempt to make them give up the meal.

 

  

The shad often appear to be too large for the gulls to swallow. I saw several gulls try to position them to get them down their gullets but the fish just wouldn’t go down. So they drop the fish in the water and then try to pick off pieces for easier eating, while fending off neighboring gulls.

  

It is unclear to me how the birds who don’t usually populate the lake in winter knew that a spontaneous buffet had appeared. In addition to the cormorants and gulls, a group of seven bald eagles (Haliaeetus leucocephalus) was also fishing when I visited. There were some almost full adult eagles (with mostly white heads and tails) and several immature birds of varying ages (eagles reach maturity at 5 years of age). I guess that they came over from Jordan Lake, which is quite a fair distance away. Searching the Internet has not yet given me an answer to this question.

I didn’t see the eagles harass gulls who had gotten a fish but they were very carefully watching one another. When the eagle below managed to get a snack, other immature eagles closely followed him/her. A sub-adult who got a fish was harassed by an immature bird as well.

 

The eagles soared overhead and were joined at one point by a beautiful red-tailed hawk (Buteo jamaicensis). The larger raptors let the hawk fly alongside them with no problem.

It was quite a chilly morning when I got to see the visiting aquatic birds, so I only stayed a short time. But my friends invited me to return for another visit, which I hope to do soon as there is no telling how long it will take the visiting birds to eat the easily available shad. And the ducks? I was able to get one rather indistinct photo of a threesome across the lake and helpful folks in a Facebook group confirmed my guess – they are ruddy ducks (Oxyura jamaicensis). Maybe I can get a decent photo of them next time. 🙂

Signs of spring in an uncertain season

As tiny snowflakes fall gently from the sky, my thoughts have left Costa Rica for a bit and turned to the weird weather we’ve been having in North Carolina. I didn’t move to this state for its weather but in the time I’ve been here, I’ve grown to appreciate the climate – we have four seasons but the winters have not seemed overly long and the spring and autumn temperatures are often fabulous.

 

This year, much of February was unseasonably warm in our Piedmont area and people, as well as plants and animals, were enjoying the warm sun and mild temperatures. Crocuses and irises poked their blooms up a bit early and birds were checking out nest boxes.

 

 

 

Butterflies, like this question mark (Polygonia interrogationis) made an appearance (it was getting sustenance from some dog poop left on a bridge!) and Carolina anoles (Anolis carolinensis) emerged to sun in the warmth.

 

 

 

Then on 12 March, we had a day of snow. The male Northern cardinal (Cardinalis cardinalis) and Carolina wren (Thryothorus ludovicianus) sat amid the flakes between trips to the feeders.

 

 

The female ruby-crowned kinglet (Regulus calendula) didn’t seem too perturbed, but the male resident was not happy – his bedraggled red crown was in evidence, both when chasing her away from the feeders and when he was just coping with the wet snow.

 

 

 

When I left for my Costa Rican rambles, it looked like the spring weather might give way to colder temperatures; when I returned 10 days later, it was definitely more winter-like. Then, this past weekend, we had a brief respite. Despite a cold morning start, friend Karla and I visited the Guilford County Farm. The farm personnel had marked off a section of the gravel parking lot where killdeer (Charadrius vociferus) had placed a nest with four eggs. When the babies hatch, they can walk away from the nest as soon as their downy feathers dry.

 

They won’t be able to fly until about 25 days later, but they can feed themselves. The parents will continue tending to and defending them, however. In the meantime, the parents do not come near the nest so as not to draw attention to it and they will try to lead any potential predators away with a broken wing display. They do fly near the nest often, however, and keep an eye on it in between their own feeding sessions.

Karla quickly spotted Wilson’s snipes (Gallinago delicata) flying over the pond and settling at the water’s edge. As we drew closer, we could spot them occasionally, but they blended really well with the vegetation. Below are a couple photos taken at a fair distance with a high ISO and lots of grain – but you can try to see if you can spot the six snipes in the first photo and the two in the second.

Fortunately, one flew in a bit later and I got a couple more recognizable photos!

  

Some Canada geese (Branta canadensis) flew in and headed for the same corner of the pond.

Then, as I was trying to find the snipe in the grass again, I noticed a killdeer looking for insects nearby.

She was accompanied by a male, who at first seemed to be preening but who was actually trying to impress her with some courtship displays.

 

The males will show off their feathers for their (potential) mates, especially raising and displaying their bright tail feathers as a fan.

The female would walk away and he would eventually move closer in an attempt to get a response.

Nearby, we saw three Northern mockingbirds (Mimus polyglottos), two of whom seemed to be males battling over a female. Their dispute was very vigorous and lasted quite a long time. In fact, when they flew away, they were still going after one another!

 

During our continuing walk in the fields and woods near the farm, we saw many other bird species including Eastern meadowlarks, brown creepers, woodpeckers and a pair of kestrels. The woods were kind of strange in that there were very few bird nests visible in the bare trees and also no Eastern gray squirrel nests – in fact, we did not see one squirrel the entire time we were there, which was very odd. An adorable baby donkey (Equus asinus) did greet us as we walked by, though, and our long excursion (about 6 hours) gave us a nice taste of spring. Hopefully, when the snow flurries today end, we will see spring weather come back quickly and be able to enjoy the flora and fauna of this season again. Next blog – back to Costa Rica!

  

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.

 

 

Water-logged and soggy birds

Carolina wren I77A2794© Maria de Bruyn resMy original intent was to write only one more blog this year, but our current weather has induced me to write two (the other will follow on the last day of 2015). During the past week, our region has had more than our “fair share” of rain. Fortunately, the house is not downstream or downhill of flowing water so that flooding is not a concern (and having helped my parents when their home was flooded with about 5 feet of water, I know that is a real pain to say the least). But the yard is so water-logged that small pools of water are scattered in many places and the ground cover squishes when we walk on it. Combined with very high temperatures for this time of year, it seems that El Niño is really making itself known – and the birds like this Carolina wren (Thryothorus ludovicianus) must be getting tired of being water-logged as well!

Sayings such as “like water off a duck’s back” imply that birds don’t really get bothered by water pouring from the heavens, but that is probably only partly true. During recent downpours, I saw – through the back porch screen – a Carolina wren and Northern cardinal (Cardinalis cardinalis) hanging out on a downspout under the house eaves, while a brown-headed nuthatch (Sitta pusilla) clung to the brick wall under the roof overhang to get out of the rain.

brown-headed nuthatch I77A0090© Maria de BruynNorthern cardinal I77A0101© Maria de Bruyn res

Birds that regularly dive underwater do have denser feathers, which helps prevent water from penetrating through to their skin, as is the case for this Canada goose (Branta canadensis).

Canada goose I77A1169© Maria de Bruyn res

But birds’ feathers are not inherently waterproof – when we see water droplets beading on their backs and tails, as in the case of this brown thrasher (Toxostoma rufum) and blue jay (Cyanocitta cristata), it’s because the birds have made them water-resistant to some extent.

Blue jay I77A3141© Maria de Bruyn resbrown thrasher I77A9881© Maria de Bruyn res

This happens in two ways. On the one hand, birds such as pigeons, herons, hawks and owls have special feathers called “powder downs” or “pulviplumes”, which are covered in a dusty powder containing keratin that disintegrates and becomes a waterproof coating. They spread the powder to other feathers while preening.

Great blue heron I77A1220© Maria de Bruyn res

Great blue heron (Ardea herodias)

brown-headed nuthatch I77A0090© Maria de Bruyn resOther birds have a uropygial (preen) gland located at the base of their tails. It produces a substance containing oil and wax that the birds spread on their feathers when they groom. Often, they will rub their head against the preen gland and then spread the oil by rubbing their head against other feathers, a behavior that this female red-winged blackbird (Agelaius phoeniceus) seemed to be doing when she was grooming. The wax then helps make the feathers more flexible and water-resistant, which explains the water beads we see on their feathers when it rains.

dark-eyed junco I77A4085© Maria de Bruyndark-eyed junco I77A9650© Maria de Bruyn res

Dark-eyed junco (Junco hyemalis)

Eastern towhee I77A9682© Maria de Bruyn res Pine warbler I77A9921© Maria de Bruyn res

Eastern towhee (Pipilo erythrophthalmus)

     Pine warbler (Setophaga pinus)

It may be that some birds are less successful in spreading the powder and wax to their head feathers, or they rub all the oil or powder off their heads onto other feathers. This may account for the “bad hair day” look some of them get when it rains for hours on end. These spiky “Mohawks” often appear in Northern cardinals and Eastern bluebirds (Sialia sialis).

Northern cardinal I77A9734© Maria de Bruyn res Northern cardinal I77A9870© Maria de Bruyn res

Eastern bluebird I77A9717© Maria de Bruyn resEastern bluebird I77A9710© Maria de Bruyn res

Other birds seem to especially get soggy feathers on the crowns of their heads just above their eyes. This may be why we see so many of them shaking their heads vigorously to get rid of the dampness on their pates.

Pine warbler I77A9942© Maria de Bruyn res White-throated sparrow I77A2980© Maria de Bruyn res

Pine warbler                                              White-throated sparrow (Zonotrichia albicollis)

Red-bellied woodpecker I77A9724© Maria de Bruyn res

 

 

 

And some birds just get an overall scruffy look when it rains hard, like this red-bellied woodpecker (Melanerpes carolinus).

 

 

 

 

Eastern bluebird I77A0155© Maria de Bruyn resThe water-logged look does seem to give some birds an angry or disgruntled appearance; I can certainly sympathize since endless days of rain – even in warmer temperatures – is one of my least favorite types of weather. It seems that overcast days and showers are continuing in our local forecast for some time to come. So the poor birds have to put up with the wet weather a while longer. We’ll all appreciate the sunlight when it comes back in force – hopefully soon!

A morning at Cane Creek Reservoir

The Orange County water authority maintains two recreational areas where it manages water supplies for our area’s drinking and sewage water. One is the Cane Creek Reservoir, where people can boat, fish, bird and relax. When my morning began yesterday with a distressing family situation, for which I would need to wait for news, I decided to visit the reservoir since getting out into nature always helps me handle stress. My foray was rewarding, both in terms of handling the emotional tension and appreciating the marvelous diversity that nature offers for our appreciation.

marbled orbweaver DK7A5291© Maria de Bruyn resMy walk began with a need to wipe spider webs from my face as our arachnid brethren were busy spinning their webs across walking paths. The marbled orbweaver (Araneus marmoreus) was in the process of building a web, climbing up and down and leaving new silken strands behind as they emerged from the spinneret.

marbled orbweaver DK7A5288© Maria de Bruyn

The walking path also held evidence of the passing of a young white-tailed fawn (Odocoileus virginianus). A Carolina satyr butterfly (Hermeuptychia sosybius) was moving from grass blade to grass stem as I proceeded up a hill.

white-tailed deer DK7A5276© Maria de Bruyn resCarolina Satyr DK7A5279 © Maria de Bruyn res

Eastern bluebird DK7A5392© Maria de BruynFirst birds of the day as I left the woods — a pair of Eastern bluebirds (Sialia sialis) that were roosting on a wire. When a pine warbler (Setophaga pinus) wanted to join them, he was given to understand that his proximity was not appreciated.

 

pine warbler DK7A5383© Maria de Bruyn res

Next, I caught sight of a Northern mockingbird (Mimus polyglottos polyglottos), very busy grooming near the top of a small tree.

Northern mockingbird DK7A5449© Maria de Bruyn res Northern mockingbird DK7A5443© Maria de Bruyn

Southern magnolia DK7A5439© Maria de Bruyn resA nearby Southern magnolia (Magnolia grandiflora) was mostly laden with rose-colored fruit but one large bloom was still vibrant and visited by smaller and larger bees.

A number of birds were singing but I didn’t recognize their calls and I saw some birds flit from one tree to another but then I caught sight of one that was dipping into the grass to pick up insects and then sitting still on a branch for a while. It was a lovely Eastern phoebe (Sayornis phoebe), a type of flycatcher with a yellow hue.

Eastern phoebe DK7A5586© Maria de BruynEastern phoebe DK7A5722© Maria de Bruyn

This bird flew around a bit, perching in trees, on ropes and barbed wire, providing some nice views of its lovely self.

Eastern phoebe DK7A5670© Maria de Bruyn resEastern phoebe DK7A5825© Maria de Bruyn res

A blue-gray gnatcatcher (Polioptila caerulea), busy as these small birds always seem to be, was gleaning insects from twigs and branches.

blue-gray gnatcatcher DK7A5924© Maria de Bruyn Blue-gray gnatcatcher DK7A5920© Maria de Bruyn blue-gray gnatcatcher 1-de Bruyn, Maria DK7A5944 Supported on the balance beam

Coming up on the shoreline of the reservoir, I first spotted some least sandpipers (Calidris minutilla) foraging at the water’s edge. This is the smallest species of sandpiper and they are also the smallest shorebirds in North America. They looked very pretty in flight.

least sandpiper DK7A6073© Maria de Bruynleast sandpiper DK7A6081© Maria de Bruyn

The sandpipers landed near some killdeer (Charadrius vociferous), who looked very large next to them.

killdeer DK7A6103© Maria de Bruyn res

red-spotted purple DK7A6143© Maria de Bruyn resA red-spotted purple butterfly (Limenitis arthemis astyanax) was mud-puddling on the shore, as was a Sachem skipper butterfly (Atalopedes campestris). A trio of American goldfinches (Spinus tristis) also dropped onto the wet mud for a brief time.

 

sachem skipper DK7A6355© Maria de Bruynsachem skipper DK7A6368© Maria de Bruyn

american goldfinch DK7A6323© Maria de Bruyn res

Several flocks of Canada geese (Branta canadensis) came in to the little lake. One group surprised me by suddenly veering in my direction and flying right in front of me, so close that they more than filled the screen of my zoom lens.

Canada goose DK7A6472© Maria de Bruyn res Canada goose DK7A6195© Maria de Bruyn res

Canada goose DK7A6205© Maria de Bruyn resCanada goose DK7A6207© Maria de Bruyn res

Near the end of my visit, a fellow birder kindly pointed out two green herons (Butorides virescens) to me. (Having binoculars is a definite advantage for this pursuit!). One was rather far away but another within walking distance so I snuck up on it in stages.

green heron DK7A6717© Maria de Bruyngreen heron DK7A6575© Maria de Bruyn

In the left-hand photo, you can imagine the dinosaur ancestor of this stalker.

At one point, the bird stretched and stared at the sky, moving its head from side to side obviously watching something – it turned out to be a juvenile red-tailed hawk (Buteo jamaicensis).

red-tailed hawk DK7A6633© Maria de Bruyn red-tailed hawk DK7A6631© Maria de Bruyn

My sneaking ever closer to the heron was rewarded when I saw the short bird catch and eat a rather large frog for its brunch. It was sad for the frog, but that is the cycle of life.

green heron DK7A6826© Maria de Bruyn resgreen heron DK7A6850© Maria de Bruyn res

And when I returned home a short while later, I learned that the family emergency had been handled for the time being. Like the fauna, our own cycles of life are also unpredictable.