If you look closely you will count at least 9 toads in shallow water at the pond's edge looking for a mate. Any movement sparked an interest by any toad in the immediate vicinity. These toads could have been picked up easily by hand as their flight reflex was numbed by their interest in carrying on the business of creating the next generation.
The male toads would sit upright to project their call or crouch down, half submerged, making the water ripple with their sharp singing.
A successful pairing allows the smaller darker male (on top) to grab the larger female in a very rigorous hug called "amplexus" in which the male externally fertilizes the female's eggs as she releases the twin egg strands posteriorly. The egg strands are visible just above the females right rear leg and were present all along the south-central shallows of the Nature Center Pond.
In the confusion and activity it is common that a calling male will be mounted by another competing male. This situation only lasts for a few seconds as reality quickly sets in. When I put my hand near the water surface two or three toads would swim over to check out the movement.
Multiple match-ups are attempted -
And quickly reconsidered
The high pitched singing of the toads was deafening, drowning out the occasional call of a chorus frog or the slow, low "creak" of the leopard frog.