Tuesday, August 23, 2011

Hands-On Learning

     The Eastern Bluebird is a common species of open and semi-open habitats. Easily recognized by their brilliant blue plumage, bluebirds are a familiar sight in my Canton neighborhood, perch-hunting for insects from tree snags, mailbox poles and stonewalls.  
     My own yard not only provides excellent feeding opportunities, it provides bluebirds with a place to nest and raise young. In a typical breeding season, our lone nest box will produce two clutches of eggs.   
     After a successful first nesting this summer, a second attempt was soon underway. As activity inside the box increased, I confirmed that a new clutch of five eggs were placed. However, in the days to follow, the lively activity that had preceded the egg laying had all but ceased. Suspicious, I decided to check the box one more time. What I discovered was truly upsetting. The bluebirds had abandoned the nest box and five eggs due to a large infestation of sugar ants.

     Disappointed, I removed the nest and prepared the box for another possible nesting attempt. I brought the infested nest down to the woods to discard it properly and bury the eggs. As I was carefully picking out each individual bluebird egg to set it down on the ground, one of them had broken in my hand. The photograph below is what I found inside the broken egg.
     Admittedly knowing nothing about the development of an egg, I turned to the book; Manual of Ornithology (Noble Proctor and Patrick Lynch, 1993) for some enlightenment. I’d like to share with you some information from the book which helped me better understand the structure and development of an egg.
 
     The avian egg is a miracle of natural engineering. Light and strong, it provides everything a developing bird embryo needs from just after the ovum is fertilized until the chick hatches.

     The avian egg is a self-contained womb in which the embryo is protected and provided with the food and nutrients it needs to develop and hatch. But the egg is not a completely closed system, shutting off all outside contact. Birds, even as they are developing in the egg, are warm-blooded animals, with all of the metabolic activity that homoiothermy demands. The chick within the egg must be able to respire, to exchange gases and water vapor with the outside world, or it will suffocate.

     The bird egg must allow an efficient exchange of gases to support the growing chick, allowing waste gases out and oxygen in. The avian eggshell is not simply a coating of calcium carbonate but a complex laminate of mineral crystals embedded within a web-like matrix of material similar to collagen fibers. Reptiles, birds and mammals are called amniotes because the eggs of all three groups develop within an amniotic membrane. The amniotic membrane forms an enclosed, watery environment that protects the developing fetus and allows it to exchange gases with the surrounding world (Carey 1980, 1983; Romanoff and Romanoff 1949).

      The yolk of the egg supplies the embryo with nutrients, storing food until the chick hatches. The yolk sac surrounding the yolk is another embryonic membrane. The yolk is approximately 30 percent lipids (fats), 15 percent protein, and 55 percent water. Fat, not protein, is the primary food in bird eggs. This gives bird eggs a significant advantage over reptile eggs, in which the primary nutrients are stored as protein, because when broken down, fats yield more metabolic energy and water per unit than do proteins. They can thus survive in much drier environments than reptile eggs.   

     The age of the embryo, from what information I could gather, is anywhere between eight to twelve days old, given the size of the formed digit and toe plates.
     Despite the loss of our five bluebird eggs, I feel there is always a way to take a bad situation and extract something positive from it.  Learning about egg structure and the developing embryo was certainly an eye opening experience, as was the actual embryo in my hand.
     I also realized that I needed to be a better steward to the birds I provide for. Whether it be a hummingbird feeder or a nest box, periodic inspections and cleaning helps ensure a birds health and nest productivity.
     Finally, I would like to thank Noble Proctor and Patrick Lynch for publishing this outstanding book. The writing is excellent and easy to understand, and the drawings are exceptional.  Roger Tory Peterson’s foreword to the book says it best; “A gold mine of facts…Every library and biology department, as well as every birder, should have a copy close at hand.”  I couldn’t agree more.

Tuesday, August 9, 2011

Mob Mentality

     Red-tailed Hawks are one of the largest and most commonly seen species in Connecticut. The other morning while driving to the Riverside Park Sewage Pond in Hartford, I caught sight of one of these large raptors resting on a city lamp post. Perched beside the hawk was a Northern Mockingbird who was highly agitated and scolding loudly from a safe distance. Having failed to elicit a response, the mockingbird then embarked on an aerial assault which involved multiple pecks to the back of the hawks head and rump. In the end, the Red-tailed Hawk gave up and flew over to a nearby woodland, but not before enduring another strike from an angry Eastern Kingbird.

     So why are avian predators like hawks and owls always the recipient of another bird’s aggression? First and foremost, predatory birds provide a major threat to most other bird species, either because there is a good chance of being eaten or an even greater chance of having their young eaten. The behavior they exhibit is called "mobbing" and is done singly or in groups, depending on the species. For those who are not familiar with a bird’s mobbing behavior, it can be recognized by an array of harsh calls, wing fluttering and tail flicking.
     Mobbing occurs mostly during the height of the breeding season as a way to distract and encourage a predator to relocate to another area. Also referred to as the ‘move on’ hypothesis (Curio 1978), previous studies have confirmed that predators are profoundly distressed by mobbing and avoid the areas where they have been harassed. The ‘move on’ hypothesis appears to be most clearly linked to territoriality (Pavey and Smyth1998).  Learn more about territorial mobbing here;
     As you can see from the photographs above, it can appear that predator harassment is risky business.  But in reality, birds who participate in mobbing are usually in very little danger. Species that are chosen to be mobbed are done so very carefully. For example, slow moving raptors like Red-tailed and Red-shouldered Hawks are less likely to strike back at an attacker, preferring to move on and save energy. Rarely would you see the same situation involve a Peregrine Falcon or Cooper’s Hawk.
Adult Cooper's Hawk in the same area two days later.
Where's the mockingbird now?
     Birders should also be aware of mobbing behavior during the winter months. On past Hartford Christmas Bird Counts, I have discovered Northern Saw-whet Owls in woodlands by following the scolding calls of Black-capped Chickadees and Tufted Titmice. David Allen Sibley writes in his book, The Sibley Guide to Bird Life and Behavior; Parids are social, bold, and inquisitive, traits that endear them to humans but make them among the most tenacious and aggressive songbirds when mobbing owls or other predators. Chickadees and titmice usually take the lead in announcing the presence of a small owl.
     Mobbing, on a rare occasion, can lead to dire consequences for the intended target. Winter flocks of American Crows often chase Red-tailed Hawks through city streets, forcing them into near-miss situations with telephone wires, buildings and even vehicles. Some, without a doubt, get injured or die as a result of these relentless attacks.
     Late last winter, I saw a Great Horned Owl get chased through the Cedar Hill Cemetery by a flock of very angry, noisy crows. When I finally caught up with the flock, the owl hung motionless by its neck, wedged between two branches. Did the owl make a mistake and stay out to long for another chance at a squirrel? If it did, it ended up costing the owl its life.  
Photo courtesy of Marcel Guerard

Friday, July 29, 2011

A Great Pond Pictorial Highlight


     Here are a few photographs I took of a Great Crested Flycatcher nest at Great Pond State Forest in Simsbury.
     The Great Crested Flycatcher is the only cavity-nesting flycatcher in North America. The nest hole is located in a dead tree stump along the edge of the pond, about five-feet from the ground.
     At the time these photographs were taken, both parents were actively catching dragonflies and feeding them to their lone nestling. Nestlings are often fed dragonflies, moths and butterflies without the wings removed.
     The Great Crested Flycatchers main winter range extends from southern Mexico, south throughout Central America, to eastern Panama.  

Monday, July 18, 2011

Signs Of Birds

     For those who enjoy watching birds, the hobby of birding can offer people many different avenues in which to pursue. More than just identification, birding involves everything from the study of various plumages, behaviors and habits, finding and documenting rarities, photography, hawk watching and banding.
     One such facet of birding I have recently discovered has been the art of recognizing bird tracks and sign. Every so often, there comes a time in the field where a dropped feather or an interesting foot print turns out to be a complete mystery.
     Some signs are quite obvious like the drilled sap wells of the Yellow-bellied Sapsucker. But others can be quite tricky. When those types of signs are encountered, birders will have to analyze each situation and look for clues to come up with the best possible explanation.  The more you observe and learn about the lives of birds, the easier it will become to interpret signs.    
     My first experience with avian forensics occurred years ago along the back trails of the West Hartford Reservoir. On an early morning hike, I happened upon the dismembered body of a red phase Eastern Screech-Owl. All that was left were two partial wings and a variety of other feathers, not much else. As I picked up the pieces to examine them more closely, I noticed that three of the feathers were different. After some careful home study, I had determined that the unidentified feathers belonged to an adult accipiter, most likely a Cooper’s Hawk.
     A more familiar sign in our woodlands are those that are left behind by the industrious woodpeckers. Of all the woodpeckers, the Yellow-bellied Sapsucker is the master of sign. The tell-tale sign of a sapsucker’s presence in an area is trees with multiple rows of holes drilled into the trunk. Even though I’m unable to locate their nest hole this summer, an active sap well in my Canton yard is a good indication there are sapsuckers nesting nearby.

Active Sap Well

     Another species that is frequently seen in my yard is the Pileated Woodpecker. Pileated Woodpeckers excavate large rectangular holes in mature trees as they search for grubs, beetles and ants. An enormous pile of wood chips below the hole is a sure sign of this woodpecker’s handiwork.  
     The largely nocturnal Great Horned Owl is often very hard to see. But a scattering of pellets under a stand of tall white pine trees may disclose a favored roost or hidden nest. Simply described, a pellet is a regurgitated mass of indigestible animal remains, comprised mainly of fur and small bones. People who study Great Horned Owls can often determine a bird’s present diet by the dissection of a pellet. They will also be able to gather information about the prey species itself, i.e. population size.
Weathered Great Horned Owl Pellet
     Bird tracks, or footprints, are a wonderful way to determine the presence and habits of a particular bird. The Spotted Sandpiper for example, is a common species whose track is found beside any freshwater body of water.  Before photographing its prints, I watched a hungry sandpiper delicately pick at the mud and chase insects along the banks of the Connecticut River in Wethersfield. A significant amount of track activity from this particular spot, both from the sandpiper and Killdeer, clearly shows an abundance of food here. Their occurrence in late June hints at nesting in the immediate area.
Spotted Sandpiper Tracks
     Winter is also an excellent time of year to look for bird sign. Not only is it simpler to find tracks in the snow, it is easier to discover nests from the past breeding season. The tree-top location of a Baltimore Oriole nest is unveiled as soon as every last leaf has fallen. Nearer to the ground, hard-to-find nests like that of a Chipping Sparrow and Common Yellowthroat allow birders to learn more about site locations and construction material.  
American Crow Track With Wing Impression
     One way to become familiar with track and sign is to study birds right in your own backyard. This is the place where you will know birds the best as well as the place you feel most comfortable in. Once you have achieved a close relationship with birds, it will become easier to identify their sign, even when they have long moved on.

Tuesday, July 5, 2011

Marsh Bird Relationships


     Station 43 in South Windsor is considered by many to be one of Connecticut’s premier birding locations. A beautiful eleven-acre marsh, Station 43 is owned by the Hartford Audubon Society and serves as one of the few breeding sites in the state for the elusive Least Bittern.
     On a hot, humid day in late June, I visited the marsh with hopes of catching a glimpse of this small heron. Like many of my past outings, achieving success with bitterns often entails a lot of patience as well as a bit of good luck. 

     As I eagerly anticipated the appearance of a Least Bittern, I couldn’t help but notice all the other wetland species flying about me. Swamp Sparrows, Marsh Wrens and Red-winged Blackbirds were all observed to be defending territory or actively nesting in a confined area of the marsh.  I thought to myself, how do all these birds breed in such close proximity, and still manage to be successful?
     Marshes are low-lying tracts of land that hold water throughout much of the year. They are dominated by thick, rooted vegetation such as cattails, bulrushes and sedges.  
     Birds that inhabit and nest in marshes are some of the least understood species amongst birdwatchers. The difficulty of entering an overgrown wetland in the summer is the probable cause for this. We know even less about the intricate relationships that play out within these lush habitats. My morning observations, though trivial, may shed light on some of those relationships.
     The first species that caught my attention was the Marsh Wren. Its lively song could easily be heard from the middle of the marsh. Since I couldn’t see the bird, I decided to use an ipod recording to help it come into view. Instead, the wren flew low and directly toward me. But before it could land, a Swamp Sparrow came out of nowhere and intercepted the wren, forcing it out of its territory. An agitated male Red-winged Blackbird also flew in to secure its boundary. 
     Marsh Wrens typically nest in isolated pairs, for good reason. This is because wrens are notorious for destroying the eggs and young of neighboring birds such as Red-winged Blackbirds, Swamp Sparrows, Virginia Rails, Sora, Least Bitterns and even other Marsh Wrens. The theory behind these destructive habits includes creating less competition for food with other marsh nesting birds and the expansion of their own breeding territory.
     Playing the Marsh Wren recording brought back memories of a time when I use to conduct call-back surveys for the Connecticut DEP in Glastonbury. I was always amazed at how fast a Virginia Rail could cross a marsh, on foot, when faced with a potential intruder. One rail I remember, parked itself at my feet for over a half-hour calling angrily. Sora is known to be even more aggressive than the Virginia Rail when it comes to defending its territory.
     The Red-winged Blackbird is by far the most conspicuous and energetic species at Station 43. Always in defense of their territorial boundaries, a minute never goes by without a chase or an aggressive response toward another bird. Here is nice description of the male and female blackbird’s territorial habits from the Birds of North America Online;   
     Male establishes and defends territory with clearly delineated boundaries during breeding season. Boundaries may shift within a breeding season (Dickinson and Lein 1987). All activities occur within territories, but male and female also forage, engage in sexual chases, seek extra-pair copulations, and prospect for other breeding opportunities outside territorial boundaries. Defense is based on conspicuousness, song and visual display, and aggressive responses to persistent trespassers (Nero 1956b, Orians and Christman 1968, Peek 1972).
     Existence of female territoriality is controversial. Female is aggressive toward others. Some authors (Nero 1956b, Beletsky 1983a, Hurly and Robertson 1984) assert that females defend “subterritories” within territories of males, but female display perches overlap extensively (Searcy 1986) and the primary aggressive vocalization (teer song) does not deter other females from settling (Yasukawa 1990). Nests are not overdispersed, as would be expected if females were territorial (Picman et al. 1988, Yasukawa et al. 1992a). Dominance status of resident female depends on order of settlement and distance from nest when interacting with other females on male’s territory
     As for my morning search for Least Bitterns, I did finally locate a single bird clinging to an alder bush. Many birders, including myself, raised concerns about the absence of bitterns this spring. Were they no longer breeding at Station 43? What I found out about this year’s late discovery is provided here, courtesy of BoNAO; 
     Because Least Bitterns are highly insectivorous, delayed breeding cycle may be a response to the life cycles of aquatic prey. Emergence of aquatic insects in temperate-zone wetlands peaks in Jun (Orians 1980) when these bitterns are feeding young. Later broods not definitively known, but temporal pattern of nest initiation suggests double-brooding may occur (Kent 1951, Weller 1961). If so, late Jun to mid-Jul in Iowa, with second broods larger than first, owing to the increased availability of food later in the breeding season (Weller 1961).
     In addition to the increased availability of food, I’d like to suggest another benefit to delayed breeding. A delay could help bitterns avoid other nesting birds at a time when they are the most aggressive. A toned down wren or blackbird may be preoccupied with feeding nestlings, rather than territory expansion. This might be enough to reduce the chances of egg loss. 
     Despite all the known conflicts associated with nesting in a marsh, there are a number of important advantages. First, situating nests in and above submerged vegetation helps protect eggs and nestlings from land-dwelling predators like raccoons. Nesting among Red-winged Blackbirds provides additional protection for birds against avian predators such as Blue Jays and Common Grackles.The abundance of aquatic prey that surrounds the nest site is essential to feeding fast growing young.
     If I had to pick one word to describe the relationship between marsh nesting birds, it would have to be tenuous. Even though I singled out the aggressive breeding nature of both the Marsh Wren and Red-winged Blackbird, it is important to realize that each and every wetland species is fully capable of defending its territory, invading nests and destroying eggs to further their own breeding success.

Wednesday, June 15, 2011

Bank Swallow Nest Colony


     The Bank Swallow is a common and localized breeder in the state of Connecticut. With their darting flight, they are often seen over larger rivers, feeding frantically on flying insects. Unfortunately for many of us, this is typically the only way we ever get to enjoy these small, brownish birds.
     Early one morning, while birding in the Hartford North Meadows, I caught sight of a flock of Bank Swallows feeding over an inlet alongside the Connecticut River. As I sat and admired their incredible aerial pursuits, I noticed that most of the swallows were moving inland, rather than toward the river.
     Curious, I made it a point to follow their movements and see exactly where they were heading. My curiosity eventually led me to a sand and gravel pit adjacent to the meadows. After a few minutes of diligent searching and skirting dump trucks, I was thrilled to have discovered a colony of Bank Swallow high upon a large mound of dirt.  
     Bank Swallows, as their name implies, use vertical banks along rivers to dig nest burrows. If available, Bank Swallows will also make use of artificial sites such as sand quarries and road-cut banks. Both of these sites allow swallows to easily excavate burrows into eroding and loosened soils. 
Bank Swallow excavating burrow

     Recognizing that this was a unique opportunity, I decided to spend some extended time with the North Meadows colony. From the cover of my car, I was able get up close and personal with these birds.
     Interesting behaviors at the nest colony included a variety of physical interactions. Constant fighting over nest holes and mates often resulted in pairs fluttering toward the ground, pecking at each other. Vocal threats and pushes also ensued when intruders mistakenly entered wrong burrows.
     Another form of behavior I observed involved the excavation of a nest burrow. At two of the nest holes, dirt was briefly seen being forced out of the entrance tunnel by use of the swallow’s feet.  A more thorough explanation of this and other burrow-digging techniques is provided here from the pages of The Birds of North America Online.
   Bank Swallows have smaller, more conical bills, and a proportionately larger cucullaris-lateral rectus muscle complex than other swallows (Gaunt 1965). Burrows are dug with the bill, feet, and wings (Stoner 1936) as birds cling to a slight projection on the bank face, and dig using their bill in a rapid, slashing motion and feet in a scratching motion. Dislodged material from inside the burrow is ejected with vigorous kicks and wriggling body and wing shuffling movements. Burrows are excavated by groups of individuals, and excavation tends to be clustered in colony so that breeding is synchronized within sections (Hoogland and Sherman 1976, Freer 1977, Sieber 1980).
     Once a burrow is completed, the terminal end (chamber) is slightly enlarged upwards and to the sides. The nest chamber floor is constructed to be level with the burrow floor. Bank Swallow nest material includes plant stems, grasses, rootlets and leaves. Clutch size ranges from two to seven eggs.  
     As important as it is for Bank Swallows to find suitable nesting surfaces, it is equally important for the swallows to have prime foraging habitat surrounding the colony. Foraging occurs widely over most open lowland habitats such as agricultural areas, wetlands, grasslands and rivers.

Friday, June 3, 2011

Weather Related "Groundings"

     In the birding world, spring migration is the most anticipated event of the year. As the temperatures rise, so does a birder’s enthusiasm to find new migrants. Picture perfect days often bring out the masses to well –known Connecticut hotspots like Hammonassett Beach State Park in Madison and Milford Point.
   Still, picture perfect days in the spring can sometimes be hard to come by. April showers bring May flowers, but it might also bring fog, wind and downpours too. These unsettled days are almost always avoided by the average birdwatcher, but not me, I prefer them.
     As a primarily inland birder, I rely heavily on weather systems to drop and delay birds that would otherwise bypass my region. For example, Red-throated Loons, White-winged Scoters and Horned Grebes are practically guaranteed to be found along the Connecticut coast during the appropriate time of year. But in Hartford County, those same species are nearly impossible to find without the assistance of foul weather.
     So how does a person who lives far away from the coast find these uncommon species? To start with, you need to keep your eye on the week’s weather forecast.  If the forecast calls for precipitation to move in during the overnight, an effort should be made the following morning to search reservoirs and lakes for grounded migrants. Secondly, dedicating yourself to a favorite location will help prevent hard-to-find species from going undetected. Persistence will eventually reap rewards.
     Batterson Park Pond in Farmington is one place I continue to check on a regular basis. Conveniently located on my way to work, this 140-acre body of water has been a pleasant surprise over the years. Last April’s weather related sightings at Batterson Pond included Lesser Scaup, Surf Scoters, Red-breasted Merganser, Horned Grebe, Red-necked Grebes and Common Loons. 

Batterson Pond in the fog and rain
     The same rules can also apply to finding migrant shorebirds. When inclement weather is encountered, shorebirds will often seek refuge within farmland or along lakeshores until migratory conditions improve. Black-bellied Plover, Sanderling, Dunlin and Short-billed Dowitcher are some of the prized inland finds.
     Clearly there are many benefits to birding inland during unsettled weather. Along with all the excitement of finding loons, grebes and shorebirds, comes the intimate encounter’s with birds that may be difficult to obtain from a coastal site.
     The next time a bit of rain cancels you’re birding plans, you might want to think twice about staying indoors. Who knows, there could possibly be a flock of ten Red-necked Grebe resting on a small pond near you!

Tuesday, May 24, 2011

Peregrine Falcons Return to Cliff Face Nesting in Hartford County


     The Peregrine Falcon is an endangered species success story. The ban on the pesticide DDT, a captive breeding program and attentive monitoring has brought the falcon back from the brink of extinction.  In fact, success has been so great, the U.S. Fish and Wildlife Service has removed the species from the Federal list of threatened and endangered species in 1999.  
     In Connecticut, the population continues to grow with ten active nesting pairs present in 2010, fledging nineteen chicks (Connecticut Wildlife Magazine; September/October 2010).
     This spring, I had the good fortune of finding a new Peregrine Falcon nest site. The nest is located in the town of Newington, on a cliff at the Balf Quarry. As you can see in the photograph below, the female has chosen a perfect bed of greenery to place her eggs. During this inaugural breeding season, the nest has produced a total of two chicks. 
Photo courtesy of Steve Grant

     Looking back, it is hard to believe that on the first day I discovered the falcons at the quarry, I was trudging about in knee deep snow and freezing temperatures. Today, I stand above the nest, peering down on two downy young and a very proud mom. Through it all, it has been a long and incredible experience.  
     The Newington location represents the second known nest site in Hartford County. The other nest, sits high upon the Travelers Tower in downtown Hartford. Still, the site in Newington represents more than just another nest location, it signifies the return of natural cliff face nesting to Hartford County.
     Exactly one hundred and fifty years ago, the first nesting of Peregrine Falcon in New England was confirmed at Talcott Mt., Hartford, on May 25, 1861. The Talcott Mountain site was deserted in 1942 because of the shooting of both adults and young by a game warden (Connecticut Birds; Zeranski/Baptist 1990). This was the last time a Peregrine Falcon attempted to nest on a natural cliff face in Hartford County.
     Dr. William Wood (1822-1885), a physician and highly regarded ornithologist from East Windsor wrote an article about the 1861 nest for The Hartford Times. Jean H. Klein, author of A Century of Birding in the South Windsor Meadows (2009) recalls the article in her book;

Writing about the Peregrine Falcon, he notes that “they are occasionally shot here (the South Windsor Meadows), within the past five years I have known three killed. There is a pair that breed on an inaccessible cliff on Talcott Mountain; and have occupied the same place for a great number of years.” He first began watching this pair in 1850, and even though it was known that he had offered a “liberal reward,” the nest was not found until 1861. It was 20 feet from the summit. The parent bird was shot and the four young taken. He kept them alive at his home and when Professor Spencer F. Baird, Assistant Secretary of the Smithsonian, visited him at East Windsor Hill he gave two of them to him in the fall of 1862. He afterwards learned that they died the next spring. He concludes his article which appeared in The American Naturalist in 1869; “It is now generally accepted that Duck Hawks nest in cliffs, never in trees.

     Despite numbers showing recent success, many Peregrine Falcons still face uncertain futures. People continue to pose the greatest threat to this raptor. Habitat destruction and nest disturbance are today’s two biggest conservation issues. A proposal to develop portions of the Cedar Hill Ridge may very well threaten the Newington nest.
     I would to thank Steve Broker of Cheshire, secretary of the Connecticut Ornithological Association, for providing me with historical information regarding natural cliff face nesting of Peregrine Falcons in Connecticut.  He has even informed me that one of the falcons taken from the 1861 Talcott Mountain nest was just rediscovered during an exhibit renovation at the Smithsonian Institute.

Monday, May 9, 2011

A Woodcock Nest


     The other day, while cleaning out the flower beds in our yard, my wife casually mentioned to me in passing that she just flushed a robin-sized bird from a brushy area. She said it looked like it was sitting on a nest. My first reaction to this was, yeah right, a bird sitting on a nest. As I walked to the compost pile, I thought about what she had just said; bird, ground, nest. Then it hit me, Woodcock!
     I ran back to my wife and asked her to show me the exact place where she flushed the bird. After some very careful searching, I was able to locate a faint, shallow depression in the brush with one beautiful egg in it. This shallow depression and egg was the first American Woodcock nest I had ever found, or seen for that matter!      
     American Woodcocks build their nests on the ground in open woods or brushy fields. Not much is known about woodcock nest building, but the one discovered in my yard looks as if a small bowl was formed with material used from the site.
     As you can see from the photographs, the eggs are a gorgeous shade of brownish orange, with small spots and slightly larger blotches.

     According to Birds of North America Online, the rate of laying eggs has not been definitively studied, but it is presumed to be one a day. I would agree with that presumption based on what was found at the nest on three consecutive days. On the day the nest was discovered, there was only one egg detected. The second day, the day I took the photos, the female had dropped a second egg into the nest. On the third day, a third egg was laid. During this sequence of laying eggs, the female was not observed on or near the nest in the afternoon or early evening. However, my wife does confirm the bird was present throughout the morning, leading us to believe an egg is placed sometime then.
     Here are some American Woodcock nesting facts I have gleaned from the pages of A Guide To The Nests, Eggs, and Nestlings of North American Birds. Baicich and Harrison.
Eggs: Usually 4, occasionally 3-5. Incubation: By female only, 20-21 days. Nestling Period: Young tended by female alone, led from nest soon after hatching, grows rapidly, can fly a little at 15 days. At 25 days well grown and fly well.  
     As difficult as it is to see an American Woodcock, it is even more remarkable to observe and photograph its nest and eggs. This is one birding memory that is sure to last a lifetime.

Wednesday, May 4, 2011

Hartford County Osprey Nests



      If you’re pressed for time and looking for a quick place to go birding, the Wethersfield Cove is the perfect choice. Located along the Connecticut River and just seconds off of Interstate 91, the cove offers a safe atmosphere, a drive up viewing area, and of course, great birds.
     Birders who visit the Wethersfield Cove are often treated to year-round sightings of Bald Eagles, an excellent chance to find white-winged gulls and waterfowl. Last year however, the cove became known for something else, a place where Ospreys nest.  
     Osprey sightings at the cove during spring migration are frequent and expected at this time of the year. But as last spring’s sightings drew closer to summer, I began to suspect that there was more to these observations that just another passing migrant. I decided to find out exactly what was going on. 
      The next morning, I once again caught sight of the Osprey, this time with a fish in its talons heading fast toward the river.  I jumped out of my car and followed a road under Interstate 91 to the riverbank. It was here where I discovered the fish-toting raptor and its recipient sitting on her nest!
     When the last Atlas of Breeding Birds of Connecticut was published in 1994, there were just a few confirmed nesting pairs along the coast, all found east of the Connecticut River. Today, the Osprey is thriving throughout the entire coastline, thanks in part to artificial nesting platforms and to dedicated people who have a strong interest in the species conservation. Ospreys have even taken to some inland sites, like Wethersfield.
     When Ospreys do decide nest inland, they will often take advantage of an open area with some sort of tall structure such as power/lighting poles.
Willow Brook Park Nest
     At this time, there are two known active Osprey nests in Hartford County. The first nest that was discovered is located in the town of New Britain, seven miles from the Connecticut River. It is placed high upon a sports stadium light tower at Willow Brook Park. This area features good feeding opportunities at nearby Shuttle Meadow Reservoir and Crescent Lake, safety from ground predators and a wide, stable platform to accommodate a large nest.  
     The Wethersfield nest site is in a little bit more of a precarious position. It is located just north of the cove outflow, on an old out-of-use oil delivery platform. Five of the nine wooden support poles that hold the platform up have broken due to old age, flooding and ice. This nest is not likely to survive many more years unless something is done to strengthen the supports.  In 2010, the Wethersfield nest fledged two young.
Wethersfield Cove Nest
Photo courtesy of Jim Woodworth
     With Ospreys becoming more successful away from coastal areas, it may be time to strongly consider erecting a couple new platforms, inland along the Connecticut River. In fact, the Great Meadows Conservation Trust has already looked into placing a platform onto one their properties.  To learn more about this excellent organization, see here:      http://www.gmct.org/
     Finding the nest last year and watching the young Osprey develop is nearly indescribable. It almost seems miraculous! Let’s hope they continue to prosper.

Tuesday, April 26, 2011

"Flicker Dance"



     The Northern Flicker is a common and widespread breeder throughout the state of Connecticut. They can be found in a variety of habitats such as open forests, semi-open country, suburban neighborhoods and urban parks.
     Flickers have unusual feeding habits, especially for a woodpecker. They spend a great deal of time on the ground foraging and probing for ants, a key component of their diet.   
     Early last spring, I had the opportunity to photograph these ground feeding woodpeckers at Keney Park in Hartford. Nothing seemed out of the ordinary on this particular morning, birds were well-spaced, their bills stuck into the dirt and focused solely on ants. The flickers stayed busy, I continued to take photos. Suddenly, without any provocation, two of the birds flew over to one another and met face-to-face. With bills held slightly upward, they began to bob and weave in a comical dance, flashing their yellow tail feathers at each other.
     What type of odd behavior was I observing? According to the Birds of North America Online, it is a combination of territory establishment, pair formation and nest-site selection. I noticed something else odd as I looked over my photos from my morning visit; there were two females dancing! What I was surprised to learn is that both sexes defend nest trees and mates aggressively. Below are some of my photographs from Keney Park as well as a professional description of this incredible dance behavior from the Birds of North America Online.   



Both sexes defend nest trees and mates aggressively. Agonistic behavior is highly ritualized in flicker “dance” (Fig. 6). Typically, 2 birds of same sex pair off in mock “fencing duels,” using their bills as “foils,” while a member of the opposite sex looks on. This dance is prevalent during early phases of the breeding cycle (territory establishment, pair formation, and nest-site selection), but is also seen infrequently and at lower intensities at other times (Short 1982). Displays that comprise the dance are clearly agonistic (Noble 1936) and function in territorial defense, but territorial establishment and pair formation are so integrated in flickers that these displays may also play a role in pair formation; this remains poorly understood.Typically, 2 birds of the same sex face one another on a branch with their bills held at a slightly upward angle (about 30° from horizontal). Each bird quickly swings its head back and forth and bobs it up and down, such that the bill appears to trace a circular or Figure-8 pattern in the air (Kilham 1959, Lawrence 1966, Short 1972). The swinging and bobbing give the appearance of a mechanically animated toy, and are usually accompanied by in-rhythm Wicka Calls from both dancers. The red nuchal patch is usually erected in Yellow-shafted Flickers. Intensity of the dances varies greatly: the dance of 2 birds (same sex) is likely to have relatively low intensity and may even be silent, but the arrival of a third bird (opposite sex) immediately intensifies both the dance and the Wicka accompaniment. In very intense interactions, which are common, the dancers flick their wings and spread or rotate their tails such that the yellow, or red, ventral surfaces of the flight feathers are clearly visible to the opponent. Bursts of dancing and Wicka-calling might last 5–10 s, followed by a 30-s period of quiescence, followed by another burst of dancing where all participants seem compelled to join in. Bouts may last nearly half an hour (but usually are shorter) and may be joined and rejoined over a period of many hours. We have observed sustained series of dance bouts go on essentially all day, involving the same participants. Variation in the dance is substantial: the apparent context, number of participants, location, intensity, duration, whether the wings and tail are spread, whether Wickas accompany animation, pattern traced by bill, etc., can all vary. No data are available that demonstrate the range of variation or its meaning.
"Dancing duels" often do not result in physical contact but instead one bird simply flies away. If one bird does not fly away after many minutes of dancing, the two rivals may peck and claw at each other and perhaps end up in a rolling fight on the ground (KLW). This usually results in a long period of one bird chasing the other, displacing it from perch to perch in short flights until eventually the "loser" flies away out of apparent exhaustion.


Monday, April 18, 2011

What Could These Ducks Be Eating?


 
     No matter where you may find yourself birding in Connecticut, it is always important to be aware of you’re surroundings. Keeping focused in the field can often lead to discoveries that would otherwise go unnoticed.
     Last week at Riverside Park, I caught sight of a small mussel washed up along the banks of the Connecticut River. As I admired the beauty of the mussel in my hand, I thought back to a sighting I had of a female American Scoter at this very location. It spent the entire month of January feeding and resting just off the boat launch. I remember asking myself, why does this bird favor this part of the river? What could it possibly be eating down there?
     The mussel I found and photographed here is called an alewife floater. It is one of twelve species of freshwater mussels native to Connecticut. The alewife floater is still considered an abundant species in the Connecticut River, where it lives in mud, sand and gravel bottoms. Was this mussel sustaining the scoter in Hartford?
                      www.ct.gov/dep/cwp/view.asp?a=2723&q=325894&depNav_GID=1655
     Another question which came to mind while I was reading about freshwater mussels, involved the occurrence of overwintering Common Goldeneyes. Why are Common Goldeneyes found in such large numbers in Enfield, and absent elsewhere in Hartford County? With a coastal diet of primarily mollusks and crustaceans, is there a similar habitat or condition in Enfield that supports a healthy population of mussels, and in turn, a healthy population of Common Goldeneye?
South River Street Boat Launch
Enfield
                          
     To help answer these questions, I turned to Doug Smith of the University of Massachusetts Amherst.  http://www.bio.umass.edu/biology/conn.river/fwmussel.html
 He wrote,
 Paul,
 Well here's what might be happening. The Enfield rapids are shallow and
the substrate is rocky with sand and silt, especially since the old pier
wore away. Many years ago (over 30) I studied that section of the
Connecticut because it was a historical location for many mollusk
species, many since extirpated. What I did find was that section of the
river was the only one that still supported a decent population of the
Virginia river snail, Pleurocera (=Goniobasis, =Elimia) virginica, a
relatively large (10-20 mmm) snail living on the hard substrate (Smith,
DG, 1980. The Nautilus 94(2):50;
http://www.biodiversitylibrary.org/item/34223#page/66/mode/1up). Two
mussels, Elliptio complanata and Anodonta implicata, were also fairly
common. Since about 1991, an invasive species of clam has become
established, the Asian clam, Corbicula fluminea, and is quite abundant
in the lower part of the river. It is possible that it has migrated
upstream to provide an additional source of food. Over the last twenty
years, due to clean up efforts, the populations of various mollusk
species have grown considerably and the last I heard was that the river
snail was everywhere and common in Enfield and elsewhere.
     With that being said, it is safe to assume the winter population of Common Goldeneyes will remain constant in Enfield for years to come. In an environment that is largely hidden, it is essential to annually monitor the health of the entire Connecticut River ecosystem. This will ensure that all living things, seen and unseen, will always flourish.  

Wednesday, April 6, 2011

Woodpecker Nest Cavities


 
     In the avian world, nesting is often considered a risky endeavor. Parasitism, predators and inclement weather can all play a factor in nest failure. But through time, woodpeckers have evolved a way to minimize those challenges by simply nesting indoors, in tree cavities.
     Woodpecker activity plays a vital role in the woodland environment, excavating holes for themselves as well as for other species of birds. Black-capped Chickadees, Tufted Titmice, White-breasted Nuthatches and Eastern Screech-Owls all depend on the woodpecker’s handiwork to nest.
     Woodpeckers typically select a dying tree wherein to nest. Its advanced state of decay aids in the cavity excavation process. However, some species like the Hairy Woodpecker prefer to nest in living trees, although it may use a dead limb if needed. A woodpeckers choice of tree species vary in Connecticut, but most favor oaks, maples, hickories, poplars and birch.      
     The construction of a new nest cavity takes place each year, approximately three weeks before eggs are laid. Woodpeckers chisel out a horizontal entrance tunnels until it reaches the trees heartwood. From there, it forms a sunken chamber in which to lay the eggs. The accompanying drawing clearly shows the finished product.
From A Guide To The Nests, Eggs, and Nestlings of North American Birds
Baicich &Harrison

     Since woodpeckers do not add any lining to the nest, eggs are laid directly on the chamber floor, or onto wood chips left over from the cavity excavation.
     I have provided some additional facts regarding woodpecker nest excavations from the web pages of The Birds Of North America, online version. 

Yellow-bellied Sapsucker
In Ontario, during 3,514 min of observation, males excavated 1,317 min, females 476 min; male excavation periods averaged 17.8 min.
Bill used to chisel out cavity, striking wood at rate of 100–300 strikes/min, periodically stopping to remove chips.
Male does nearly all excavation of nest; female spends much of time preening and resting and removes very little wood from cavity, but will become more involved in excavation if first cavity not successful.

Northern Flicker
Usually excavates nest cavities in dead or diseased tree trunks and large branches, in Wisconsin, 92% of nest cavities were in dead trees.
Nest cavity is excavated by “chiseling” away small chips of wood with bill; bird starts by clinging to trunk, using its tail as a prop, then perching on lower lip of nest opening as it works its way into interior. Periods of chiseling are interspersed with shorter periods of tossing chips from cavity opening; chips are also carried away in bill.