I joined Henry K, Srini & Kamala R, and Rosie R early yesterday evening (10/17) to observe the annual October Tree Swallow swarm east of Tracy yesterday. We observed well over 20K over the lush green corn fields to the immediate south by standing at the fishing access along Tom Paine slough just off Canal Blvd. Having observed this phenomenon in past years (2008, 2013, and 2018), this appeared to be considerably reduced from those years, but nevertheless very impressive. We really had to strain our eyes to see the countless dark specks in coordinated flight in the waning light. Unfortunately, once you find these birds, it is a race with the setting sun, so there is no time to go racing off to find a better viewing spot, but afterwards I checked a map, and it looks like better/closer viewing might be had from W Arbor Ave, just west of the large farm operation at Arbor & Paradise Rd. Photography was impossible due to the fading light & distance.
Remember, this is an ephemeral phenomenon—the birds will probably be gone by this time next week or earlier if the farmer chooses to harvest the corn. (We heard several repeated gunshots, apparently an attempt by the owner to the east to discourage the birds from settling in the corn—even though swallows are insectivores and whose only interest in the corn is to find a safe place to rest for the night.) These birds are largely migrants from the Yukon and British Columbia on their way south to Mexico for the winter.
Be aware: evening weekday traffic along the freeways here is HORRIBLE, so if you’re gonna go, I’d recommend today (Sunday). Please report your success (or not) via this listserve or eBird (or both).
Relevant eBird reports are:
|2013-10-25 17:50||Tree Swallow roost A (2013)||San Joaquin||US-CA||View or edit ||
|2013-10-24 18:00||Tree Swallow roost A (2013)||San Joaquin||US-CA||View or edit ||
|2013-10-22 18:00||Tree Swallow roost A (2013)||San Joaquin||US-CA||View or edit | |
|2013-10-21 18:00||Tree Swallow roost A (2013)||San Joaquin||US-CA||View or edit | |
|2013-10-20 18:18||Tree Swallow roost A (2013)||San Joaquin||US-CA||View or edit | |
|2013-10-19 18:10||Tree Swallow roost A (2013)||San Joaquin||US-CA||View or edit|
|2018-10-11 18:35||1039–1599 W Lorenzen Rd, Tracy US-CA (37.7273,-121.3227)||San Joaquin||US-CA||View or edit |