Cycles in biological systems are all pervasive in nature. Birds like any other species express daily rhythms in activity/rest, hormone secretion and several other rhythmic characteristics. Most bird species also show long-term cycles in feeding behaviour, body fattening (in migrants), reproduction, moult or migration. Both daily and seasonal behaviors are under the strict control of the endogenous clock mechanisms, but the role of environment remains critical for optimal performance and ultimately the survival. Synchrony with the environment is achieved through interaction of clock component with external cues (e.g. photoperiod), and internal co-ordination among different rhythmic physiological correlates is achieved through neural and endocrine signalling. Thus, we are interested to learn about how birds achieve precision in timing their daily and seasonal activities in sync with the periodic environment. Our research effort mainly centers around the “Avian Circadian and Seasonal Systems: Study from Behavior to Molecules”. The working hypothesis has been that specialised cells localized in different tissues express genes involved in the clock circuitry, and different cell populations control the food intake, body fattening, reproductive axis, moult and migration, in a way that each event can be timed and spaced with each other to optimise an ecological adaptation.
- Clocks controlled daily and seasonal behaviors (e.g. migration and reproduction).
- Neurobiology of seasonal behaviors. Seasonal changes in the song control system. Developmental changes in the brain (neurogenesis/ synaptogenesis) in response to seasonality and hormone status. Hormonal modulation of brain functions.
- Endocrinology of seasonal behaviors (with reference to changes in melatonin, thyroid and steroid hormones).
- Physiology of migration. Identification of (novel?) genes/ proteins involved in initiation and termination of seasonal behaviors.
- Metabolism: glucose uptake studies in response to daily and seasonal changes.
- Identifying the changes in gene expression and protein levels in relation to changes in the reproductive and migratory status, and determine whether these changes allow normally diurnal birds to become nocturnally active during the migration. Also understand how migrants function at a high performance level despite having very little sleep.
- Endocrinology of free-living birds. Measurement of hormones, and recording their behavioral changes.
- Clocks and cognition and learnt behavior in corvids and songbirds.
- Clock and metabolism using migratory birds as model systems.
- Studying orientation mechanism in migratory songbirds.
- Life style patterns and biological clock mediated functions in human
Non-migratory and migratory bird species
Techniques We Use
- Un-obstructive monitoring of nocturnal behaviors including sleep by video recordings
- Continuous monitoring of activity and feeding by infra-red sensors
- Anatomical modifications in the brain in relation to seasons and physiological status
- Endocrine manipulations (removal of hormone source and replacement)
- Hormone assays
- Non-invasive study of seasonality (feather regeneration and molt, body fattening, food intake and feeding behavior, plumage and bill color scores etc.)
- Metabolic activity through respirometer
- In situ hybridization and Immunohistochemistry.
- PCR and Real time quantitative PCR
- Song recording
- Orientation facility (in progress)