Borrego Valley Hawkwatch: March 2015

Friday, March 27, 2015

Two Weeks of Solid Hawks!!! March 21-28, 2015

Leaders:
March 21-Rose
March 22-Wes
March 23-Herb
March 24-Steve
March 25-Laura
March 26-Pam
March 27-Hal

Migration:
March 21-176 Swainson's Hawks; 2 Turkey Vultures
March 22-224 SW's
March 23-19 SW's
March 24-502 SW's; 1 Red-tailed Hawk; 1 Osprey
March 25-292 SW's; 4 TV's
March 26-121 SW's
March 27-471 SW's; 4 TV's; 4 Unidentified Raptors

Discussion:
Another remarkable week with daily reports of large kettles of Swainson's Hawks both in the flower fields (feeding on caterpillars) and migrating. Finally today we might have cleared out some of the hawks that were lingering in the area feeding. We will see if new hawks enter the valley today and this evening. The weather continues to be very hot with temperatures in the 90's and total blue skies. Tomorrow the temperature may crack 100. There has been very little morning wind and it appears that thermal production was minimal. The hawks appear to struggle upwards before using updrafts along the Santa Rosa Mountains. Most of the migration has been along the mountains. Below are some youtubes of a typical caterpillar digging in and an evening kettle.

We cannot predict the outcome of the next few weeks. This evening will tell the tale. I might update this blog if new information surfaces this evening. Oh oh, it's almost 6P and I just got word that over 200 hawks came in!!!

http://youtu.be/S3J6jxb1Xks http://youtu.be/dxIzfe0YDew

Juvenile Light Intermediate-HC

Evening at the Watch-HC

Beautiful Turkey Vulture-Gary Hilton

Friday, March 20, 2015

Unusual Week-Many Hawks Spending Time In Town-March 13-March 20, 2015

Leaders:
March 13-Rose
March 14-Hal
March 15-Wes
March 16-Herb
March 17-Laura
March 17-Steve
March 19-Joe
March 20-Hal

Migration:
March 13-0
March 14-116 Swainson's Hawks
March 15-52 Swainson's Hawks; 34 Turkey Vultures
March 16-145 Swainson's Hawks
March 17-192 Swainsons's Hawks
March 18-0
March 19-9 Swainson's Hawks
March 20-326 Swainson's Hawks

Discussion:
Almost every day we had Swainson's Hawks on the ground feeding on caterpillars. The caterpillars of the White-lined Sphinx Moth must be very tasty. Hundreds of hawks have been staying in the valley eating the critters. See the life history below. So each day we have some migrants, some hawks staying and new hawks entering the valley. Hawks are arriving all afternoon. They most likely see other hawks on the ground and zero in on the feeding grounds. It has been a chore to count hawks this season. Mainly because of the change in typical behavior. Only a fraction of the hawks on the ground migrate each day. As of March 20th estimates of the number of hawks in town is around 600. I have been raising some of the caterpillars (feeding them California Primrose from my yard). They now have entered the Pupa stage. I am patiently waiting until they become adult flying moths. I began the project March 10. Also below is the adult Painted Lady and the Chrysalis (same as pupa). There are perhaps a few hundred thousand Painted Ladies in the valley. Check out the Youtube for March 13-http://youtu.be/isKSi24qOrw

Typical Moth Life Cycle

Adult White-lined Sphinx Moth-HC

Moth eggs on underside of a leaf

Sphinx Moth from an egg-Iris Kilpatrick

Pupa of the Sphinx Moth-Light Brown-Upper Caterpillar becoming Pupa-HC

Painted Lady Butterfly Just Before Adult Emerging-HC

Painted Lady Just Emerged on Pin-Cushion Flower-HC

Sphinx Moth Tracks-HC

Nice Shot of a Swainson's Hawk-Barbara Barnes

Thursday, March 12, 2015

A Wild Week-Caterpillars Everywhere and Hawks Feeding on Them-March 7-13, 2015

Leaders:
Saturday March7-Rose
Sunday March 8-Wes
Monday March 9-Herb
Tuesday March 10-Steve
Wednesday March 11-Laura
Thursday March 12-Joe

Migration:
Saturday-466 Swainson's Hawks; 24 Turkey Vultures; 1 Red-tailed Hawk
Sunday-141 SW's
Monday-220 SW's; 29 TV's; 1 Red-tailded Hawk; 1 Peregrine Falcon; 1 Prairie Falcon
Tuesday-449 SW's
Wednesday-8 but might be updated
Thursday-Around 600 SW's

Discussion: The flowers are blooming and hundreds of thousands of caterpillars are eating the flowers. Hawks are all over the valley eating the caterpillars. So we have had lots of activity and migration. Separating the migrants from hawks staying in the valley to feed has been difficult. Both the day and evening events have been spectacular. Our photography-Iris Kilpatrick has produced some magnificent photo's of individual Swainson's Hawks. Channel 10 (ABC-San Diego) ran a featured segment on the flowers, caterpillars and hawks. Some of the Youtubes and an interview with Joe Hopkins were included. We expect the flowers to dwindle during the current heat wave. The caterpillars are fat and will probably dig in-pupate and spend the year underground. They will emerge next winter as moths and hopefully will experience more flowers to pollinate. Yes, the flowers depend on the moths and at the same time provide food for the growing caterpillars. Check out the current Youtubes below. This youtube was taken at 7P, yesterday March 12th. http://youtu.be/3ycsJ4NQ8F4

Iris Kilpatrick

Hal

Just a Reminder-Be Careful-This Sidewinder was found at the entrance to the evening watch-run over by a careless driver. Also, watch out where you step. Our very hot weather now will bring out more snakes.

Paratropper and SW's-Hal

Our Eyes-Steve and Rose-Hal

Friday, March 6, 2015

Results February 28-March 6th-Exciting Migration Tuesday March 3rd-399 Swainson's Hawks

Leaders:
Saturday February 28-Hal
Sunday March 1-Herb/Judy
Monday March 2-Herb/Judy
Tuesday March 3-Steve
Wednesday March 4-Laura
Thursday March 5-Hal
Friday March 6-Rose

Migration:
Saturday Feb. 28-0
Sunday March 1-0
Monday March 2-5 Swainson's; 7 Turkey Vultures; 1 Red-tailed Hawk
Tuesday March 3-399 Swainson's Hawks; 27 Turkey Vultures; 1 Red-tailed Hawk
Wednesday March 4-44 Swainson's Hawks; 17 Turkey Vultures
Thursday March 5-0
Friday March 6-0

Discussion:
Borrego Springs had a two day rain event-Sunday and Monday. Monday evening we expected some hawks (counted around 250) but were surprised with over 300 on Tuesday. The total of 399 included several close kettles with lots of fine viewing. The photo's below will give you an idea of the excitement. Of course we hope for a few more repeat days with plenty of hawks. Check out the Youtubes below. On Thursday we watched as several Swainson's Hawks descended into a field near the hawk watch. On Friday we counted more than 50 in flower fields. Evidently the same birds are spending time feeding on caterpillars. This evening (Friday) we counted 67 Swainson's in a field next to the date farm on Borrego Valley Rd. This is just south of the solar field. Apparently hawks are remaining in town as long as there is food available.

Typical Behavior of Swainson's sitting in an open field. This photo was taken last year. Today the same field has a number of hawks feeding on caterpillars.

Evening Watch:
We enjoyed watching the SW's feeding in the field across from the evening site. Our high count was 67 hawks. No new birds apparently came in.

Prediction:
Wind should be calm in the morning so any flight from the date farm will take place after 8:30A. Best viewing will be from Borrego Valley Rd (night site-1.8 miles north of Palm Canyon Drive). If the hawks migrate they will cross DiGiorgio Rd near Big Horn (about 2 miles north of Palm Canyon Drive). The hawks will stream out of the date farm and kettle up to the west.

ALERT LIST:
If you would like to be placed on the ALERT list-contact Hal at Raptorhal3@gmail.com I only send out an ALERT when we have over 100 Swainson's Hawks descending into the valley in the evening. You can access data from 2003 to present at Hawkcount.org.

Thanks to Iris Kilpatrick who continues to come out to photograph the hawks on short notice. Also, thanks to Charity Hagen and Laura Webb for sharing photos.

Attached are several photo's and a two Youtubes-enjoy. All shot March-3-5, 2015

Hawkwatch Youtube: shttp://youtu.be/Swhy_cREPqs and http://youtu.be/_rlGjxBS2Fc