Histophysiological responses to formalin stress in some passerine birds belonging to different ecological habitat

The objective of the present investigation was to study the relationship between the thyroid gland responses to formalin stress and the ecological habitat in some passerine birds. In view of this birds from two different ecological habitats (arid and swampy climates) were selected for this investigation. Acute exposure to formalin stress induced thyroid gland hypertrophy almost uniformly in all the birds irrespective of the difference in their habitats. It is suggested that the thyroid gland activity induced by stress is not directly related to the ecological adaptation in these birds.