Saturday, May 10, 2014

The Last of the Summer Frogs

The wet season was very short lived this year. Within about two weeks of the only significant rain for the summer, most of the summer frogs had stopped calling. This was due to little follow up rain and the early onset of the colder weather. The numbers of several species was down significantly compared to the last few years. I would expect that the severe drought was the main contributing factor. On the other hand some other species have increased in numbers. At least the wet season did arrive and give an opportunity for the frogs to breed, even though it was for a shortened period. Hopefully enough have breed to boost the numbers of frogs back to similar numbers. During the few weeks after the rain many species were out breeding in good numbers so time will tell if the breeding season was long enough.

In the last few days before most of the summer frogs had stopped calling I went for a walk around the property. Most of the same species were sighted as in my last post except for the Northern Banjo Frogs, Dainty Tree Frogs and the Keferstein's Tree Frogs. There was a noticeable decline in numbers of  every other species that was sighted compared to the few weeks prior. I only took a few photos as it was getting late and I was determined to get a decent photo of the Tyler's Tree Frog for this season, which took quite a while.

A few Ornate Burrowing Frogs were spotted. This one was out in the open so it was easy to get a good photograph. As mentioned in other posts this frog can be extremely variable in colour/pattern and even skin texture. I have several, very different colours/patterns of these frogs on the property. This colour variation has been seen on the property before but is less common than the other colours/patterns found here. The shape of these frogs is quite distinct, along with the protruding eyes, but to be certain for identification, all specimens have a distinct plain circular patch between their eyes, on their back.

Ornate Burrowing Frog side view

Ornate Burrowing Frog top view, showing the circular patch between the eyes

I had to wade across the creek again to get to the Tyler's Tree Frogs. I could hear a couple calling from the house which is why I actually went out frogging briefly tonight. Luckily one of the two was sitting reasonably low on a branch, overhanging the water. It took quite a while to get a photo as I couldn't look through the eyepiece of the camera due to the height of the branch. I am concerned about the limited number of Tyler's Tree Frogs sighted and heard this year. They have only ever been heard in a small stretch of one creek on the property and only three or so were heard at one time this season. They were always in limited numbers on the property. About 25 - 30 individuals is the most I had seen and heard at any time, and most nights when they were active they usually numbered between six and twelve.

The left side of this creek is the only place the Tyler's Tree Frogs are found

Back view of one of the Tyler's Tree Frogs

The other specimen of the Tyler's Tree Frog

The same Tyler's Tree Frog as above

Tyler's Tree Frog calling

The Green Tree Snake below was in the same tree as the two Tyler's Tree Frogs. It would be one of the longest specimens that I have seen of this species. It would have been close to two and a quarter metres and had 6 distinct lumps in its belly. Most of these I presume would have been frogs. After the snake was in the tree I only heard the one Tyler's Tree Frog call out for the remainder of the night. Hopefully the Green Tree Snake didn't eat one.

Green Tree Snake

This is a recording of the advertising call of the Tyler's Tree Frog. The first frog heard in the recording is actually a Peron's Tree Frog and it continues to call throughout the recording in the background. The loud "laughing" frog in the foreground is the Tyler's Tree Frog. Eastern Sign-bearing Froglets can also be heard continually throughout the recording. They have the high pitched "eeek" sound. The occasional Eastern Dwarf Tree Frog can also be heard.

Several Peron's Tree Frogs were seen and many more heard but this was the only one that I could access easily to photograph. They look very similar to the Tyler's Tree Frogs and Roth's Tree Frogs. I get all three of these species on my property and all three are known as the laughing tree frogs. The Roth's can be easily distinguished from the other two species by the colouring of the pupil. To identify Peron's Tree Frogs and Tyler's Tree Frogs is more difficult as they are more similar in appearance. I find the Person's Tree Frogs here have a rougher textured skin and darker markings, but this is not always the case. The blotching and patterning can change between the species so this isn't a reliable way to identify them. The best way is to observe them calling as their call is the best way to identify them, which is what I do. The Peron's Tree Frogs also have tiny green specks scattered over the dorsal surface and legs. Sometimes these specks can be hard to see though.

One of the several Peron's Tree Frogs that were sighted

The same Peron's Tree Frog from above

Peron's Tree Frog

Tonight the big Green Tree Frog on the veranda didn't want to come out of his day time hiding hole.

The big Green Tree Frog

Tonight was the first time that I had sighted the Broad-palmed Rocket Frog this season. The quantity of this species on the property is always much less than the Striped Rocket Frogs but they can usually be seen most nights after decent summer rain. This was not the case this year! The Striped Rocket Frogs would have numbered many thousands on the property. Several hundred could be seen easily most nights after good rain in a small area whereas the Broad-palmed Rocket Frogs I would estimate in the low hundreds and maybe less. The most I have ever seen in one night would have been about 30 individuals.

Broad-palmed Rocket Frog

The same Broad-palmed Rocket Frog from above

The Broad-palmed Rocket Frog from above

The biggest decline in frog numbers I noticed this year was with the Rocket Frogs. Each night less than 150 Striped Rocket Frogs were found and significantly less where heard calling throughout the property compared to the last four years. For the entire year I only sighted two Broad-palmed Rocket Frogs on the property!! Hopefully this decline in numbers was just due to the drought and the numbers pick up again in the coming years if we get better rain spread more consistently throughout the summer. Nothing else has changed in the last two years like slashed areas of the property and the times when the property is slashed. I will get a better indication of factors that effect the frog populations, the longer I observe the numbers and species of frogs on the property, the weather, farming practices etc on the property. I have something very unique here and I do everything possible to help increase the populations of the native animals.

This is a recording of the advertising call of the Broad-palmed Rocket Frog.  A Cane Toad can be heard at the beginning of the recording in the background.

The Cane Toad was located and disposed of humanely. Very few are heard calling around the property now due to me gradually removing them over the last 4 years.

More pics and updates when more frogs are photographed and recorded.

1 comment:

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