This week’s observations at the NBG.
The little pond is much smaller due to the dry weather, and the rain friday night did not enlarge it. The arrowroot(I think) (the emergent plant with purple fllowers in a spike) makes it very difficult to see more than a few feet from shore, so hard to know what is going on, but in the one area that I can still see into the water there are only a few tadpoles left, and these have lightened in color and developed legs. Looks like this latest hatching class will be gone very soon, joining their conspecifics in the woods. Yesterday I thought I saw a bullfrog tadpole, and the bullfrogs are still around, but again, with limited visibility it is hard to know.
Plenty of action over at the big pond. It appears that all of let years tadpoles have now become froths, with hundreds around the edge of the pond. While I was not watching the number of jumping tadpoles rapidly diminished and the number of frogs on shore expanded. Looks to be nearly complete, and now in the water you are seeing the much smaller rings and lower jumps of the new crop of tadpoles, probably very similar to the bullfrog tadpoles I saw in the little pond.
I saw two muskrat one day this week, I saw a night heron this morning. And walking home there were a pair of goldfinch along with the usual assortment of robins, jays, sparrows, flickers, hawks, and doves.
This week the little pond in the NBG is shrinking fast while at the same time every day a new crop of tadpoles comes out of the water as little tree frogs. It is the second year I have kept track of the timing, and this year the tadpoles are morphing a bit earlier than last year.
On a beautiful June morning I went over to the NBG to check out the life. On my way in I saw an Oriole. I think there is a pair in that neighborhood. At the large pond I counted 14 turtles, which is the highest number I have ever counted there.
Several years ago 6 was the high for the year, last year it was 9. They line up on the log sunning themselves as the morning starts to get warm. They range in size from small to large, seemingly 4 or 5 ages classes represented.
The little pond is in full swing with its brief Gray Tree Frog tadpole season, with the first tadpoles appearing May 19, and this week the earliest of the hatchings, (3 or 4 several days apart producing noticeably different size classes) the largest tadpoles have developed legs. Tree frog tadpoles tend to either be swiftly on the move, eating, or lying on the bottom sort of dug into the mud. There are hundreds if not thousands in the pond.
This year I have noticed a second type of tadpole which despite much observation time the previous two years, I had not seen before this year. I think they are bullfrog tadpoles, as last summer a crop of about 20 bullfrogs came over from the larger pond as part of the new frog dispersal that follows the transformation from tadpole to frog. I know at least a few of them made it thorough the winter.
The tadpoles are bigger, greener, and have a more transparent tail than do the tree frogs. What they also do is move quite differently, with today the noticeable habit of hanging out tail down int he water column near the surface and occasionally breaking the surface readily observed. This is exactly how the big second year tadpoles act in the larger pond, supplemented with large jumps by the big tadpoles. Like breaching whales in miniature. The new babies are not jumping yet, but you can see it coming.
I get to the NBG in the dark all winter, but rarely6 when the days are as long as they are now. But after I got home front he EJ conference I went over to the NBG and just after 9 PM the little pond was loud with the calls of at least 2 different kinds of frogs. Going ho have to check the recordings of what is what before I can offer identification of the callers.
I went down to the North Burial Ground twice today. It is a beautiful June day, it rained hard yesterday, but sunny and 70 today. At the big pond there were turtles sunning in the morning and we watched the fish. At the little pond I saw my first tadpole with legs.
When i went back this afternoon at the big pond I saw a Great Blue Heron eat two fish, once on my way in, and once on my way back from the little pond.
The little pond had filled back up after yesterday’s rain, and with that the Gray Tree Frog tadpoles were much closer to where you can stand with dry feet, and for some reason there were many more around than I have seen on any day so far this spring. There are still some very little ones, some larger ones, and some that are starting to sprout legs.
I also saw another kind of tadpole, just 3 of them. They were a different color, a lighter gray, with a clear tail, and yellow spots. They also swam differently from the tree frog tadpoles. The pond did have an invasion of Bullfrogs last fall, and they breed later, so it could be bullfrog tadpoles, but I need to do more research.
The other animals of interest today in the NBG included a hawk being chased by little birds, and oriole and a goldfinch.