The time, of the year for the frogs' annual ritual
by Paul Cormacain
PART of the annual ritual of wildlife is to record frogs coming together at the beginning of the year. This is the. time when they are highly visible, and thus highly vulnerable to predators. This is the time of year for eggs and spawn, for tadpoles and small frogs, for the annual great gathering of these weird and wonderful creatures.
I had experienced the yearly congregating much earlier, but there always seemed to be other things of interest, so the frogs were put on the long finger. Then I saw some spawn in an unexpected spot last week, so now it is time fo remark on the frog life.
Frogs started to head for the breeding grounds perhaps a few months ago. You may have come across the odd one when it was crossing the road on a wet night, for they have a strong sense of direction, and must go to the traditional breeding grounds. If roads get in the way the frogs have to cross them, and that can present a problem for cars can go faster than frogs.
So many motorists kill frogs, although chances are most drivers will be unaware. The desire for self-propagation is very strong in the frog, and self-preservation can take a knock, especially when the knocker is a gigantic, heavy, mass of steel, a motor car.
Most people associate frogs with water, but it is only in the first months of the year that the creatures live there.
The rest of the year frogs are to be found on land, although they tend to not advertise their presence. So they are rarely seen.
This year's frogs are likewise good at hiding but they break the rules by hiding in weeds and water for the first number of months, then taking to the great outdoors.
We saw the frogs crossing roads on dark wet nights. We saw them at some of their usual ponds, gearing up for the old self propagation thing. The males and females come together, then swim in tandem for some days. The males grow horny pads on their front feet, enabling him to grip the female's slippery skin, for when in tandem the male sits on top of the female.
As mentioned, this is the time of year of high visibility and is danger time. The males fight to win a lady's hand and this can be an exhausting business which can cause death.
Then again, some of the creatures will be exhausted and not take elementary precautions for their own safety. This leaves them more liable to predation. When her time comes the female will lay anything from one to three thousand eggs. Simultaneously the male ejects his sperm so that all the eggs are fertilised as they come into the water.
All the eggs are shed in one batch, this event usually occurring early in the morning.
Job done, they recuperate, sometimes in deep water, then they move ashore till next year.
The eggs start to swell on contact with the water, and they float on the surface. As breeding spots are traditional many frogs will usually have gathered there, so more and more egg deposits become larger and larger, and frequently the water is covered with frog spawn.
Tadpoles hatch after two or three weeks, and swirl and feed and try to avoid capture.
External gills are absorbed at about four weeks. The hind legs appear at about seven weeks, and by week twelve the tail is absorbed. The front legs emerge. The lungs are used.
In spite of best endeavours, most of the eggs, tadpoles, young frogs are eaten by fish, insects, animals, birds, and few remain to leave the water for a ground existence at June or July. Three thousand eggs may produce a few frogs who mature.
What precipitated me to write about frogs was seeing thousands of eggs in a few damp patches last week. I suspect the frogs miscalculated, thought they had found a fine breeding place, and bred. But a small drought would dry out these patches, and I do not think that the creatures would survive.
It seems to be much wasted effort to me, but I can hope I am wrong.
Coming Events
Saturday 9, daily to Saturday 23 - Family trail around the grounds of Castle Espie to celebrate Saint Patrick's Day and the corning of spring.
Saturday 16, Sunday 17 March - National Science Week, recycling paper is the theme, 2pm, details from Castle Espie, 91874146.
Friday 22-Sunday 24 March - RSPB/Birdwatch Ireland, joint conference. An exciting agenda has been arranged for this conference to be held at the Great Southern Hotel in Rosslare.
Sunday 24 March - Ranger Ramble at Colin Glen Forest Park. at 2pm, details 9061 4115
Monday 25 March - Lisburn RSPB will have Anthony McGeehan tell you how to Know Your Birds better, 7.30, Friends Meeting House, phone 9260 1864
Thursday 28 March - Birdwatch Morning, 10.30, Castle Espie, see flocks of birds, call 91874146
Saturday 30 March - Lisburn RSPB field trip to Rea's Wood and Sixmilewater, talk to 9260 1864
Friday 29-Saturday 30 March - Sounds messy, but try to get involved in the biggest ever Easter Eggsculpture, at Castle Espie, from noon, call 91874146
Sunday 31 March -More eggs, this time at Oxford Island, and it involves a self-guided trail around the Nature Reserve, and the mystery of the mixed-up eggs, at 12.00, call 38322205
Ulster Star
15/03/2002
