The Nesting Season, 2023

The nesting season 2023 showed a slight increase in numbers of nesting pairs of Cliff Swallows in Massachusetts from 2022, although the total number of colonies in the state decreased. In 2020 there were 285 nesting pair among 12 colonies statewide; in 2023 there were there were 280 nesting pair among 7 colonies statewide. It is clear that Cliff Swallows have a tenuous foothold in the state; this is consistent with downward trends seen in MA and other New England states for decades. In MA, in all cases but one, the colonies that disappeared or declined were those with House Sparrows present. Increases at several sites appeared to be the direct result of House Sparrow control and social attraction after the installation of artificial clay nests.

A colony that saw increases in numbers of nesting pairs seen below; this site increased from 3 pairs of Cliff Swallows in 2021, to 9 in 2022, to 15 in 2023. House Sparrow control was implemented here in 2022 along with installation of artificial clay nests. The farming practices here do not include the use of pesticides.

Our favorite colony! This colony is thriving! The are naturally no House Sparrows at this site, and the colony has been growing with the addition of artificial clay nests, which you can see in the video below, from 2023.

Barn Swallows continue to slowly increase at Patten Hill (see graph below); the greatest threat to Barn Swallow nesting success at our site (and other local sites) appears to be infestation of nests and nestlings with mites. To control for mites we use artificial clay nests, which we clean and replace between first and second broods; in severe cases we clean chicks, nests, and replace nesting material. Photos: Artificial clay nest with mud added by swallows; Barn Swallow chicks after cleaning of mites.