12 August 2024
On Friday I wrote a couple of swarm of dragonflies. Lately it’s a swarm of swallows.
On 31 July my sister watched greater than two dozen tree swallows swarm over her backyard in Tidewater Virginia. They have been feasting on flying insects for roughly 20 mins, after which they have been long past.
Once they end breeding, tree swallows (Tachycineta bicolor) accumulate in ever-growing flocks in July and August and start their southward migration. In transit they search out swarms of bugs that can come with true flies (Diptera), dragonflies and damselflies (Odonata).
Top tree swallow migration happens in early to mid-fall. I used to be at Cape Cod on 1 October 2017 after I witnessed an enormous flock at West Dennis Seaside. Considerable insects attracted the tree swallows; plentiful swallows attracted a falcon who captured one in his talons (best proper of photograph underneath).
On 6 October 2021, Mike of Mike’s Nature Connection witnessed a identical flock on Cape Cod.
See this map for your self at eBird Standing and Traits > Tree Swallow > Weekly Abundance.