Of Pacific Chorus Frogs, Milkweed Plants, and Cow Patties

July 25, 2023

The long days of summer called the “dog days” are upon us and there are some unusual plants blooming and creatures hopping around. In some areas of Little Lake Valley, it is hard to walk without causing the ground to erupt with small iridescent Pacific Chorus Frogs, Pseudacris regilla, hopping everywhere. Residual, warm water is left behind from the abundant winter rains and spring inundation, often into late summer. This is the best environment for Pacific Chorus Frogs to lay eggs by the millions. In late February and March, there is a deafening sound of male frogs singing to attract mates. Once eggs have been laid and fertilized, the tadpoles hatch and spread out into the deepest areas. As the summer heat intensifies and evaporation occurs, the tadpoles are on a time clock to get their legs and become adult frogs. When this happens, there are some really teeny tiny frogs hopping around. Their tiny size is astonishing! Another wonderful thing about these frogs is the variety of different colors they come in – gold, greens, reds, and browns to grey. They have a base color that doesn’t change but enough of their body can shift to a color closer to their background environment that they can camouflage easily.

As we have stated in an earlier blog, Pacific Chorus Frogs are the most common North American amphibian. They are erroneously called Tree Frogs, rarely found in trees but instead preferring being on the ground or in short shrubbery. One plant that the frogs enjoy climbing up is the Showy milkweed plant, Asclepias speciosa. When my colleagues and I are out looking for Monarch eggs and caterpillars on this plant essential to their life cycle, we often find many little Pacific Chorus Frogs hiding in the curled or folded leaves of these plants. We have not found them in the Narrowleaf milkweed, Asclepias fascicularis. The clue as to why they are there might be found in another place where we commonly find these diminutive frogs.

Last week as I was deciding to write this blog, I was talking to one of our consultants who is doing botany work on the project. She told me about an experience her and another botanist had had that same day with chorus frogs. She said that they noticed an abundance of the frogs on the fresh laid cow patties. They observed as many as eight of them on one! Then as they closely watched these frogs, they noticed that many small flies were landing on the cow poop at the same time. These frogs had a smorgasbord of flies to choose from at any one moment. I had to see for myself, so I went to the site where they had done their observations with phone in hand ready to make a video. It was surprising how easy it was to find the patties and the frogs doing what frogs do best, eating flies! What fun I had waiting patiently for one little frog to feel comfortable enough with me so close that it would go ahead with its regular behavior of catching and eating flying insects. Happily, it worked out. As I walked around the outside of one of the woodlands on the Mitigation Project, it was astounding how many baby frogs were hopping around and taking advantage of the cow patties as a source for gathering food, just as they probably have in the past when other large grazing mammals dominated the landscape. This phenomenon illustrates the ecological connections that take place in a functioning environment that normally are not thought about. It was abundant habitat and food for the Pacific Chorus Frogs.