||Frogs may live in the pond over winter as they can breathe through their skin but most frogs return to the pond (by jumping) to mate in Spring from their hibernating places on land. Their skin is smooth and shiny and often covered with blotchy markings. The males return first to the pond they were raised in and attract the female to themselves by croaking. They mate in shallow areas of the pond amongst plant growth. |
||Once he has attracted his female he will grip her from above with his forelimbs in an embrace called 'amplexus'. The female will then lay spawn which is fertilized by the male as it is released. The female will use plant growth to support herself during this process as she can be suffocated. The mating can last for days and more than one male can mount one female while she is laying spawn.|
Froglife (the wildlife charity for conservation of amphibians and reptiles) advise that frogspawn is not taken from one pond to another to help control the spread of invasive pond plants and amphibian disease.
Each female usually produces one clump of frog spawn in a season usually in warm days in March. Frog spawn is laid as lumps about the size of a tennis ball made up of jelly and eggs on shallow shelf areas and then as they mature these lumps swell to grapefruit size and float to the water surface so that many can merge to look like one jelly mat.
Pond conservation are asking pond owners to take part in the Big Spawn Count 2014 to see how many lumps of spawn appear in your pond so they can see how many breeding females are reported.
Big Spawn Count 2012 count results: The average number of spawn clumps in garden ponds was12 equivalent to 12 breeding females visiting. It was quite common for people to report over 20 clumps. Bigger ponds (classified as 5m in diameter) had more spawn, with an average of 28 clumps and the smallest garden ponds had an average of just over 6 clumps.
Big Spawn Count 2013 count results: similar volumes of spawn were produced in 2013 but at least 2 weeks later due to the cold Spring with 2 peaks - one in mid March and the second in mid April. The average number of clumps remained at 12 with 60% of people that completed the survey reporting 10 clumps or less indicating 10 visiting females. Click to read the full results.
||Over the weeks of spawning many frogs will appear in the water and a mass of movement and frog spawn can be the result. Our pond had over 40 frogs in it at one point and created at least 15 balls of spawn which soon merged together as a swollen mass of jelly that would protect the eggs. The juvenile frogs not yet capable of mating (3 years old) may appear in the pond too.|
The adult female lays several thousand eggs to allow for huge losses - each in a clump of jelly with dark brown-black centres but a clump of spawn will sit half submerged under the water and half exposed to the air and so vulnerable to being killed by overnight frosts. Very cold weather can interrupt spawning - a second batch of frogspawn may appear in your pond once the cold weather subsides. Dead eggs will have grey or white centres. In a light frost only the spawn closest to the surface will be killed the rest may survive as they are insulated from the cold in the centre of the clump. If a small amount of spawn has died leave it in the pond and it will break down or get eaten by other creatures but a large amount of decomposing spawn jelly can overload the pond with nutrients so take it out and put it on the compost heap.
Live frog tadpoles will live on the jelly at first that provided protection before they hatched out and will then survive by eating algae and vegetation in the pond. They are brown in colour. Once they start to develop legs, tadpoles change from being vegetarians to carnivors. Most established ponds will have enough food for the tadpoles to develop to maturity.
|Many tadpoles are eaten in Spring - up to 90% of the eggs, tadpoles or froglets in the pond are lost to predators (dragonfly larva, water boatmen, snakes or birds as they swim together in the warm shallow waters at the edge of a pond. They need as much cover from plant leaf as possible so they have somewhere to hide from these predators. This would include Myosotis species, Veronica beccabunga and in a larger pond area - Mentha aquatica, Menyanthes trifoliata and Rorippa nasturtium-aquaticum.
Garden ponds are often home to more than one species of amphibian - see newt and toad sections - this is a healthy situation and shows that the pond is functioning well. A cyclical predator-prey relationship will establish where the numbers of one will control another until all becomes balanced eg newts are a predator of frog tadpoles especially in the weeks immediately after frog spawning when adult newts are in the pond laying their eggs on the same pond plants the tadpoles are swimming in.
Adult frogs can be affected by Frog red leg - ranavirus - on hot days between , as it is most virulent at temperatures above 25°C. rogs may appear with:
Abnormal wasting (emaciation).
Redness of the skin (erythema).
Skin ulcers or sores.
Bleeding (systemic haemorrhaging), especially from mouth/anus.
Breakdown of limbs (limb necrosis).