Feature Article September 25, 2002
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Autumn Farewell It's time to say "so long until spring" to a denizen of our ponds and quiet waters. The Bullfrog may already be in hibernation as it is the earliest of the frogs to settle deep into the mud in the bottom of ponds where it will spend the winter. The adult Bullfrog is also one of the last of the frogs to emerge from its winter home in the spring, but once it does, its 'jug-o-rum' as its call is sometimes described, may boom across the landscape from late May until early July on warm evenings. The deep bass tone may be heard as far away as a kilometre. In the spring, male adult Bullfrogs will each establish a breeding territory which they will aggressively defend against other males. Lying on the surface of the water exhibiting their bright yellow throats, their mating calls will attract females. In the excitement of mating, a male will sometimes seize another male by mistake, and the unwilling recipient of this error will give a release call, described like "someone with a bad cold blowing his nose', and he will be freed. However, if it is a willing female that is grabbed, she will release her eggs, which will be fertilized externally by the male. The eggs form a large, white, frothy mass that floats on the surface of the pond and a mass will contain up to 20,000 eggs. The tadpoles are tiny when they hatch, but by late summer they will be about 10 cm. long. They, too, will spend the winter buried in the mud, and emerge earlier than the adults in the spring. Then in late summer they will transform into miniature Bullfrogs, but will not reach breeding age or adult size for 2 to 3 years. Adult females may reach 20 cm in length (not including the legs) on maturity, with adult males slightly smaller. Bullfrogs prefer warm, weedy permanent ponds and lakes. This stay-in-my-pond (would you call him a stick in the mud?) is wary and will leap from the edge or dive and sink to the bottom of the water to escape predators. Herons, snakes, otters, minks, raccoons and skunks enjoy it as food, but another predator is man, as frog legs are considered a delicacy. The Bullfrog itself will eat small birds such as ducklings, other frogs, fish, young turtles or perhaps its own tadpoles or Bullfrogs smaller than itself. In fact, anything that it can fit into its mouth will be taken. And sometimes it will turn the tables on a snake that is hoping to have a meal, and the snake may end up in the frog's stomach. The tadpoles eat algae and water insects, and many predators feed on them, such as the Giant Water Bug. If you startle young Bullfrogs as they rest on lily pads or the shore, they will leap into the water giving a distinctive "eeep" call. If you hold an adult Bullfrog by the hind legs, it may let out a startling scream or squeal. Have you heard the "eeep", the "jug-o-rum", the squeal or scream, or the release call? Something to listen for next spring! Observations - The first day of Autumn there were a number of different species of warblers passing hrough, including Yellow-rumped, Black-throated Green, Nashville, and Black-and-white. Blue-headed Vireos were also present, occasionally singing their song. A small flock of Canada Geese were flying south. Call me at 268-2518 with any unusual sightings.
