BOMBINA VARIEGATA (LINNAEUS, 1758)
YELLOW-BELLIED TOAD

Order Ecaudate Amphibious - Anura Rafinesque, 1815 (or Ecaudata Scopoli, 1777, or Leaping - Salientia Laurenti, 1768)

Bombinatoridae Family Gray, 1831

Fire-Bellied Toad Genus - Bombina Oken, 1816

The genus comprises 8 species out of which only two are found in Ukraine: Bombina bombina (Linnaeus, 1761), Red-Bellied Toad and Bombina variegata (Linnaeus, 1758), Yellow-Bellied Toad.

The size of the body of a yellow-bellied toad is small and is approximately 27-50 мм, the coloration of the upper part is usually dark green with indistinct small dark spots. There are well developed sharply spined warts on the back. The belly is brightly colored: there are large dark (black) spots on the yellow and orange background, the yellow and orange area is usually larger than the dark part. Males have no resonator yet during the mating season, dark mating corns develop on the first three digits of the forelegs and on the lower part of the forearm. The tips of the upper part of the big digits of the fore limbs are often tinted bright yellow. The pupil is triangular.

Status. II Category of the Red Book of Ukraine - "endangered species"; the species is also listed in the Appendix II of the Bern Convention ("animal species under special protection").

Biotopes. Amphibians of this species are rather flexible and inhabit various habitats in the Carpathians and the adjacent regions: pine, deciduous and mixed forests, poloninas, shrubberies, meadows, fields. Here they are found in still or slow water bodies (lakes, ponds, puddles, canals, reservoirs), sometimes in water bodies with a relatively fast flow (on the banks of streams and rivers). There is data that in the Carpathians yellow-bellied toads are less demanding to the pollution level as compared to red-bellied toads and can live in water bodies with a relatively high level of organic fertilizer, as well as with a high degree of salinity and even in mineral springs.

Number and Tendencies to Change. The number of yellow-bellied toads in the larger part of its natural habitat can often exceed 1 toad per 0.02- 20 m². According to route records of these animals, their number on 100 m of the route often ranged from 10 to 50 toads. Their largest number was noted in small water bodies in foothills and low hills (350-600 ones, up to 900 m above sea level). It’s likely that the significant ecological plasticity of this species allows it to maintain its stable number despite the changing modern landscape. Thus, the latest records show that in June-July 2004, on the Uzhok pass on the border of Lviv and Transcarpathia oblasts at 855 m above sea level (N 49°00.051, EO 22°53.768) they numbered up to 15-20 toads per 50 m of the route and at one of the tributaries of the Rika river on western slopes of the Carpathians (the vicinity of the village of Soimy, Mezhygorsk rayon, Transcarpathia Oblast, 565 m above sea level) - 28 toads per 50 m of the route.

Biological Characteristics. They usually begin their seasonal activity in March-April. Almost immediately after hibernation (approximately in 5 - 6 days) when the water temperature reaches 12°С they start their mating. Usually, the female lays about 100 or somewhat more spawn berries as a whole laying or in portions (10-30 spawn berries) and often attaches them to various subaquatic objects: plants, branches, stones. The spawning period is extended and can last till August with not only species in amplexus but also tadpoles in metamorphosis present in the same water body. The duration of the metamorphosis is about 2 and more months. The size of the young of this year upon completion of metamorphosis is approximately 16-20 mm. The beginning of winter hibernation often depends on weather conditions and the height of the place but most often it falls on end September - early November. Usually, winter hibernation happens on land in hollows under stones, tree roots, in rodent holes, etc. Sometimes, active toads were noticed in thermal springs in winter. During winter hibernation they were found together with other amphibious species (tritons, toads, frogs) and reptiles (viviparous lizards, common grass-snakes). It’s characteristic of yellow-bellied toads to assume certain protective behavior such as demonstration of their brightly colored belly and the lower part of their limbs. They reach reproductive maturity at 3 years old.