Breeding Swallows

Barn Swallow (juvenile)

Six species of swallows breed in the Ottawa area, and most are easy to find. Tree Swallows like open fields and agricultural areas, particularly where there are lots of natural tree cavities or nest boxes. Barn Swallows also like open fields and farms, but need water in order to build cup-shaped nests of mud on the walls of man-made structures, such as the undersides of bridges and in the rafters of barns or other open structures. Purple Martins nest almost exclusively in man-made houses that can be single gourd-shaped boxes or large multi-cavity apartments; it is difficult to find colonies away from human settlements these days, at least in the east. Northern Rough-winged Swallows nests in burrows or cavities in various substrates, particularly near water, and often use circular drainage holes in the cement walls along bridges and canals. Bank Swallows also nest in burrows and cavities, but are much more particular about using vertical cliffs or banks along streams, lakes, or man-made quarries where they nest in colonies of 10 to 2,000 pairs. Finally, Cliff Swallows – personally the most difficult swallow species for me to find in Ottawa outside of a few known colonies – nest on buildings, bridges, and other man-made structures close to fields or pastures for foraging, and a source of mud for nest building.

Of these species, the Barn Swallow is the species that nests closest to me, at the Eagleson storm water ponds. Tree Swallows used to nest here, too, until the nest boxes were removed during the reconstruction of the ponds in 2016 and 2017. It used to be a common sight to watch the Barn Swallows bringing food up to their nests beneath the wooden footbridge, but after the reconstruction the underside of the bridge was covered with some sort of steel wire mesh. I thought that meant the end of the Barn Swallows nesting there, too, but it seems they are quite resilient and built their nests just inside the various drainage pipes that connect to the pond.

On July 2nd I visited the ponds and was happy to discover both Tree Swallows and Barn Swallows present and feeding their young. The Tree Swallows there surprised me more, as I heard the begging calls of the fledglings coming from a grove of trees next to the water. I couldn’t see them until I walked around to the other side of the pond, where I observed one adult flying in to feed four youngsters sitting in the branches of a tree. That was the only time I ever saw that swallow family there; I am guessing they didn’t actually nest there, and later left to find somewhere else to feed.

While walking around the ponds I found at least four fledgling Barn Swallows perching on the metal railings of the bridge closest to Hope Side Road. At least four adults were zipping around, catching insects on the wings and bringing them to their offspring. I parked myself at the other end of the bridge and took a couple of photos of the young Barn Swallows waiting to be fed.

Barn Swallows (juveniles)

Although the juvenile birds sat quietly in between feedings, as soon as one of adults swooped in with a food delivery they opened their mouths and cried out for food.

Barn Swallows (juveniles)

The easiest way to determine whether a bird is a juvenile – when they aren’t having food shoved down their throats – is to check their bills: the fleshy gape is visible extending out from where the upper and lower parts of the bill meet. The gape is often orange or yellow in colour, and it is thought that these bright colours help make the mouth more visible to the parents in the shadows of a nest cavity or leafy tree. As the bird ages, the gape will shrink, turn dull, and become unnoticeable.

Barn Swallow (juvenile)

Eventually the swallows caught on to the fact that they were being watched. Busted!

Barn Swallow (juvenile)

I continued my walk around the ponds, and found many of the usual resident birds: one Green Heron, one Killdeer, two Spotted Sandpipers, a Northern Flicker, a Warbling Vireo, six Cedar Waxwings, a Yellow Warbler, and 18 Common Grackles, including a fledgling being fed.

Seeing the juvenile swallows made me realize that I still needed Purple Martin for my Ottawa year list, so I drove over to Dick Bell Park, first stopping in at Andrew Haydon Park. The summer season isn’t as dynamic as the fall, but I still enjoyed seeing the flycatchers (one Eastern Phoebe and one Eastern Kingbird were present), as well as the herons (only one Great Egret and one Black-crowned Night Heron today). An American Redstart was also a nice find.

The swallows at Dick Bell Park are easy to find. In the warmer months their musical chirps can be heard overhead as they forage high up for insects. The large apartment-style nest boxes can be found close to the water just inside a small fenced-off area. The activity at the nest boxes is constant during the breeding season, with both male and female adults delivering food to the juveniles waiting inside the boxes.

Purple Martin (adult male)

The Purple Martin is our darkest swallow. Adult males are a shiny purplish-midnight blue with dark brown wings and tail. The adult females and immatures are much grayer and duller with a whitish lower belly. Male Purple Martins are the only swallows with a dark belly. This field mark, along with the large size and forked tail, make them easy to identify when flying high up for food. They tend to fly higher up than other swallows when foraging; if it weren’t for their musical chirps, sometimes I wouldn’t even know they were present.

Purple Martin

Females and juveniles are more difficult to differentiate. There are two of the main differences according to Sibley. First, females are a dingy grayish-brown below from throat to undertail, with smudgy markings; in comparison, juveniles are white from the belly to the undertail with fine streaks. Second, the back and crown of the head are deep blue in females and gray in juveniles. The bird above looks like a juvenile given the white underparts; however, it looks like a male with blue feathers coming in where a female would be gray.

The bird below is trickier, and I will leave that one’s age and gender as unidentified. What’s interesting is none of these birds have the obvious, brightly-coloured gape seen in the Barn Swallows above.

Purple Martin

Swallow populations have declined considerably in the past half-century, so it was great to see evidence of them breeding around Ottawa. Summer just isn’t the same without these colourful birds flitting over ponds, rivers, and pastures, eating so many of the insects that we humans find undesirable.

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