A Curlews Farewell I tried but I can try no more I cried but I can cry no more I failed to bring a young chicks cry into this world Time now bids me say farewell The sun is setting and I must go But I will come again next year and try Until I die. J.N. Allen (U.S Fish & Wildlife Service) Wildlife Reproduction So many definitions! What affects wildlife reproduction? How does reproduction affect population dynamics? How do mating habits affect productivity? How does understanding reproductive physiology & behavior help me as a biologist? Who cares? Wildlife Reproduction Females only? (U.S Fish & Wildlife Service) Wildlife Reproduction Fecundity Fertility Natality Recruitment* Rate b = ind./ind.*time Management Implications Wildlife Reproduction Productivity Recruitment Surplus or yield produced # offspring surviving dN/dt* Biotic Potential Population Size Time ABC Wildlife Reproduction Sex Relations/Mating Habits Monogamy Polygamy Polyandry Polygyny Promiscuity Management Implications (U.S Fish & Wildlife Service) Wildlife Reproduction Sex Ratios % males:% females 36:64 # males/# females 1 buck/2 does # males/100 females 2 males/100 females Wildlife Reproduction Sex Ratios Primary Fertilization 50:50 Secondary Birth ~50:50 Tertiary Juveniles Quarternary Adults (Recruited) (U.S Fish & Wildlife Service) Wildlife Reproduction Sex Ratios Influences Mortality/decimating factors Harvest, weather, disease, etc Mating habits Monogamous Polygynous Polyandrous Wildlife Reproduction Effects of Age Management Implications? Age Reproductive Value (V x ) Mammals & Birds Herps & Fish Wildlife Reproduction Factors Influencing Annual Reproductive Success Onset & length of breeding season Litter/clutch size Prenatal survival Survival of newborns Parental care Age at sexual maturity Sex ratios & mating habits Population density Wildlife Reproduction Factors Influencing Annual Reproductive Success Onset & length of breeding season Environmental factors & implications Biological clocks Timing: conditions, fertilization, & satiation JanMarMayJulSepNov Northern Bobwhite HatchingSeverest Conditions Covey Breakup & PairingCovey Formation Hunting SeasonEgg Laying Wildlife Reproduction Factors Influencing Annual Reproductive Success Litter/clutch size Environmental factors & implications Age Region Timing/season Nutrition Manageable NOAA Photo Wildlife Reproduction Factors Influencing Annual Reproductive Success Prenatal survival Gestation & incubation Fertility v. natality Environmental factors & implications Nutrition & habitat Sex ratios (e.g., deer) Manageable Wildlife Reproduction Factors Influencing Annual Reproductive Success Survival of newborns* Environmental factors & implications Nutrition & habitat Manageable Northern Bobwhite Ruffed Grouse Wildlife Reproduction Factors Influencing Annual Reproductive Success Parental care Environmental factors & implications Parental Effort Survival Rate Parental Offspring Wildlife Reproduction Factors Influencing Annual Reproductive Success Age at sexual maturity* Environmental factors & management implications Morton and Cheatum (1946) Northern NY Overbrowsed, poor soil, & deep snow 4 % of fawns pregnant Southern NY Adequate forage, better soil, & less snow 36 % of fawns pregnant (U.S Fish & Wildlife Service) Wildlife Reproduction Factors Influencing Annual Reproductive Success 100 juv F 1 st breed at age 3 (Ad) 1 juv F/age 3+ F/yr Yr 0: 100 Yr 1: 100 Yr 2: 100 Yr 3: 100 Yr 4: 200 Yr 5: 300 Yr 6: 400 Yr 7: 500 Yr 8: juv F 1 st breed at age 2 (Ad) 1 juv F/age 2+ F/yr Yr 0: 100 Yr 1: 100 Yr 2: 100 Yr 3: 200 Yr 4: 300 Yr 5: 400 Yr 6: 600 Yr 7: 900 Yr 8: 1300 Age at sexual maturity = delaying recruitment + twinning effects Manageable Wildlife Reproduction Factors Influencing Annual Reproductive Success Population structure 2 factors (population ecology) Age or population pyramid Age Class Male FemaleMale FemaleMale Female Wildlife Reproduction Factors Influencing Annual Reproductive Success Sex ratios & mating habits Monogamous Environmental factors & management implications Sex RatioMax. # nests/100 birds 50: : :7525 Wildlife Reproduction Factors Influencing Annual Reproductive Success Sex ratios & mating habits Polygynous Environmental factors & management implications Sex RatioMax. # nests/100 birds 50: : : Wildlife Reproduction Factors Influencing Annual Reproductive Success Sex ratios & mating habits Polyandrous Environmental factors & implications Sex RatioMax. # nests/100 birds 50: : :7525 Wildlife Reproduction Factors Influencing Annual Reproductive Success Population density Many welfare & decimating factors Density-dependence Population Density Reproductive Rate A B Wildlife Reproduction Factors Influencing Annual Reproductive Success Population density Density-dependence & habitat Population Density Reproductive Rate A BC Allee Effect Wildlife Reproduction Reproductive & Courtship Behavior Mate attraction Intraspecific recognition Stimulate & synchronize copulation (U.S Fish & Wildlife Service) Trade-offs Evolved with certain conditions Habitats & management Wildlife Reproduction Courtship Behavior Management implications Survival & sex ratios Many birds & ungulates Lekking spp. (U.S Fish & Wildlife Service) (Forestryimages) Wildlife Reproduction Courtship Behavior Management implications Sage grouse - Lek (Forestryimages) Wildlife Reproduction Courtship Behavior Management implications Sampling (U.S Fish & Wildlife Service) Wildlife Reproduction Reproductive Physiology & Behavior Biological clocks Implications Brain & Endocrine System Other animals Photoperiod* Other resources Water Climate/weather Cover Food Mating behavior Social behavior Molt/shed Migration Dispersal Fat deposition Gonad development Space Wildlife Reproduction Reproductive Physiology & Behavior Implications Space as a Welfare Factor Crowding, disturbance, & other stressors General adaptation syndrome (GAS) or non-specific stress response Stressor Pituitary Gland ACTHAdrenal Cortex Corticoid Hormones Growth Water Balance Glucose Metabolism Disease Resistance Development of Sex Organs and Behavior Other Wildlife Reproduction Imprinting Permanent learning during the critical period Implications (U.S Fish & Wildlife Service) Wildlife Reproduction Who cares?