From his description and photos, amateur birders were able to identify them as yellow-crowned night herons.
The Audubon Society describes the birds as being slate gray with a black head with white cheeks, yellowish cheeks, a black bill and orange legs.
It stands about two feet tall and has a wingspan of nearly four feet. Its call is described as a loud, harsh squawk.
When Pell spotted the birds, he just had to take a picture.