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.

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!