Wednesday, March 29, 2017

March 28-29-Is Migration Slowing Down?

March 28-Hal
March 29-Laura

March 28-0
March 29-160 Swainson's Hawks; 6 Turkey Vultures

It appears that migration is slowing down. The evening of March 28th did see a group of SW's descend into the valley. There are still caterpillars present in the valley. This may attract more hawks. It's hard to imagine more hawks after the record breaking numbers that we are experiencing. Today March 29th was fun with several small kettles visible to the onlookers.

We keep getting questions about the caterpillars and also the distance that our hawks fly.
1. What is the cycle of life for the White-lined Sphinx Moth
2. Why are the moths called sphinx moths.
3. Where are the hawks coming from and where do they go.

Today we'll work on question number one. See the life cycle below. When the caterpillars burrow into the sand, they pupate into a form that remains underground for 8-15 days before changing into a moth. After spending nights feeding and pollinating wildflowers, they lay eggs on the underside of the flowers. They hatch into very small caterpillars that begin to eat 24 hours a day on the flowers. After growing 3-4 inches in length they begin the cycle again.

Evening Watch: Wednesday March 29:
No hawks encountered but some may come in late.

We'll find out tomorrow.

Pupae and Adult
White-lined Sphinx Moth Eggs
Different color forms-White-lined Sphinx Moth


  1. Wow, thank you for sharing such an informational and educational post with us. I didn’t know that some moths are caterpillars before they turn.

  2. Wild life is a vast subject and requires alot of research. Just like on a simple butterfly. About its life cycle. Its worth sharing the whole cycle.