Spring is the time of year when many bird watchers and raptor enthusiasts travel to the Borrego Springs area to see the annual Swainson’s hawk migration. These hawks have one of the longest bird migrations traveling all the way from Argentina north to Alaska and the western boreal forests of Canada. The breeding range of this medium-sized brown hawk is extensive and they can potentially breed anywhere in the western United States and Canada during the summer months.
The reason why these hawks congregate in the Borrego Valley area is because of the flowers. No, they don’t eat flowers, but they do love to eat the caterpillars which munch on the plants. During good flowering years, there will be plenty of sphinx moth caterpillars to support hundreds of migrating hawks. This year, one observer counted over sixteen-hundred hawks in the Henderson Canyon area. These hawks not only eat insects, but also eat small mammals and occasionally birds, including borrowing owls. One observer even photographed one of the hawks carrying off a snake.
The best places to view the Swainson’s hawks are on north Di-Giorgio Road, north Borrego Springs Road and Henderson Canyon Road just before it turns right towards the Peg Leg Monument. At certain times of the day, such as early morning, the hawks can be found walking around on the ground. After the hawks have had their fill, they may begin ketteling, or flying around in the air in large numbers. In the evening, they will also kettle before roosting for the night. On the ground, they look to be about the size of a common red-tailed hawk and are an even medium-brown. In the air, they have various patterns light brown with dark brown streaks on their necks and chest and their wings are tapered and pointed ends. Some individuals may also appear to be all brown and are known as a “dark morph.”
The hawks are nearing the end of their migration season, but are still occasionally being reported. Sightings may continue for about another week before the hawks move out of the area and travel to the north. Already, they have been spotted passing through the Los Angeles areas.