Swainson's Hawk Migration: A banner day on March 16!


Lance Benner
 

Greetings Everyone,


Swainson's hawk migration in Los Angeles County today appeared to start rather slowly, at least over Altadena and northern Pasadena where conditions were gloomy with low clouds, fog, light drizzle, and very little wind until around mid day when things began to open up.  Then things got more interesting.


The first report of Swainson's hawks we heard about were reported by Tom Benson to our east in Redlands (in San Bernardino County), who saw about 130 around noon.  At 14:45 Tom Miko reported 87 in Claremont; some of those could have been birds seen earlier by Tom Benson to the east. At about 4 pm Luke Tiller reported groups of 42 and 58 in Altadena on the east side of Eaton Canyon near Midwick Dr.  


Then the floodgates really opened: at about 6 pm Cathy McFadden and Paul Clarke reported about 200 hawks at Claremont Village.  Mike San Miguel reported about 500 starting at about the same time, so it seems likely that he saw some of the birds seen by Cathy and Paul plus about 300 more.  Mike posted a  photos and a spectacular video on his eBird list at:

https://ebird.org/checklist/S131077579


It turns out that there were even more!  This morning Joshua Mitchell found 10 Swainson's hawks in Monrovia at 9:14 am and then another group of 15 at Vina Vieja Park at 12:39.  Starting at 12:10, Jack Wickel counted 112 farther south in Pasadena at Tournament Park (next to Caltech)in groups of 83, 24, plus a few stragglers.   Jack also posted some fascinating images on his eBird list: 

https://ebird.org/checklist/S131072975 


We also received a second-hand report of about 50 Swainson's hawks at the California Botanic Garden in Claremont this morning but I don't have any additional details.  


Here's a summary of groups of at least 10:

2023 Mar 16  50   California Botanic Garden      

2023 Mar 16  10   Monrovia, Hillcrest & Magnolia Joshua Mitchell. 9:14

2023 Mar 16 112   Tournament Park, Pasadena      Jack Wickel 12:10. Flocks of 83, 24, & stragglers

2023 Mar 16  15   Vina Vieja Park, Pasadena      Joshua Mitchell.  12:39

2023 Mar 16  87   Claremont Village              Tom Miko.  14:45  Seen from Wheeler Park.

2023 Mar 16 100   Midwick Dr, Altadena           Luke Tiller. About 4 pm.  Flocks of 42 & 58.

2023 Mar 16 200   Claremont:Indian Hill/Foothill Cathy McFadden & Paul Clarke.  6 pm.

2023 Mar 16 510   Claremont Village              Mike San Miguel; also Tom Miko and Cathy McFadden. 6:04-6:23 pm.

Some of Mike's were probably in the same group seen by Cathy & Paul nearby.


These are the largest numbers of Swainson's hawks documented in Los Angeles county this year.


Clearly substantial numbers of Swainson's hawks were on the move in Los Angeles County on March 16: Apparently more than 700 birds in multiple kettles.  It's interesting that all of these birds were seen north of I-10, which follows the pattern dating back to at least 2017, the earliest year in eBird that I've checked in detail.  


It's also intriguing that Steven Lima reported 10 at Glen Helen Park at about 1 pm. How many move through the Cajon Pass?  This would be a good area to check. 


Given that about 500 were seen at Claremont Village shortly before sunset, it seems likely that those birds roosted near that general area, and as a result, there could  be large numbers lifting off on Friday morning and moving west.  Observers west of Claremont and along the foothills have the potential to see hundreds on Friday morning, so please keep watching! Please report your sightings on the county listserve, and as always, please report them in eBird. 


Good luck, and keep looking up!


Regards,


Lance 


Lance Benner

On behalf of Los Angeles Birders

lbenner@...


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