In majority of birds, the reproductive commotion is restricted to a favorable but short period of time. This results in crowding of several physiological and histological changes during its breeding state. Such changes take place in both sexes for successful breeding. Jungle Babblers are termed social/co-operative breeders because of the fact that the breeding pair is assisted by other individuals of the flock (termed as “helpers”). These helpers forgo their own breeding and show allo-parental behavior and help the parents in taking care of all the reproductive chores except egg formation and laying. To understand the breeding cycle, histological and histomorphometric studies of gonadal tissues were carried out in these birds. The testicular cycle of Jungle Babbler could be roughly divided into seven stages showing different types and numbers of germ cells. As per histomorphometric studies, the seminiferous tubule diameter and germ layer thickness increases in breeders. Interstitium reduces in diameter in breeders but is densely packed with leydig cells resulting in high steriodogenesis. Ovaries also show varying degree of follicular maturation in breeders, non-breeders and helpers. The breeding ovaries had maximum number of large follicles with largest diameter. The granulosa cells of the mature follicles are responsible for the production of progesterone the fact which is also supported by the progesterone titers. The non-breeding ovaries consists of maximum number of small follicles in cortical region whereas helpers show both mature as well as small follicles along with large number of atretic follicles. Helpers show intermediate number of mature follicles which results in subdued production of progesterone. Progesterone is responsible for parental behavior as well as oviduct development. Helpers lack a fully functional and active oviduct due to subdued progesterone levels but the titers are enough to evoke the allo-parental behavior in them. To support the findings, in this paper hormonal titers (viz. testosterone, progesterone (Bharucha and Padate; 2009), cholesterol and ascorbic acid concentration in gonads in different individuals are also represented. Therefore, considering the lack of knowledge of reproductive biology about Turdoides striatus,the purpose of this paper consists of reporting a study on testicular and ovarian cycle in breeders and helpers. From this study it could be inferred that gonads of jungle babblers show cyclicity of development and regression during breeding and non-breeding states.

Key words: Jungle babbler, testicular cycle, mature follicle, atretic follicle.