Effects of resource availability on juvenile dispersal and settlement

Dispersal & Resources central determinant of a species’ ecology energetically expensive dispersal behaviour related to physical condition or access to energy reserves

Energetic mediation of dispersal Belding’s ground squirrel (Spermophilus beldingi) Nunes et al Greater flamingo (Phoenicopterus ruber roseus) Barbraud et al Common lizard (Lacerta vivipara) Massot and Clobert 1995 Spanish imperial eagle (Aquila adalberti) Ferrer et al photo by Don Baccus photo by Howard Inns photo from Smithsonian Institute photo from Just Birds

Resource paradox Do increased local resources encourage or provide an advantage for dispersal or philopatry? Photo by Sébastien Descamps

Dispersal trade-off Costs energetically expensive predation risk territory quality Benefits avoid kin competition avoid inbreeding territory quality

Objectives and Expectations Determine energetic influences on: growth rate exploratory forays degree of dispersal or philopatry territory takeover attempts size and quality of territory settled successful settlement and survival

maternal food supplementation autumn 2003 to Spring 2004 autumn 2003 n=31 females winter 2004 food add n=15 control n=13 Team Lloyd

Number of breeding females

Number of females surviving control

food-add control 20-Mar 03-Apr 17-Apr 01-May 15-May 29-May 12-Jun food-addcontrol Parturition dates

Litter sizes food-add control

Juvenile emergence Number of emerged vs failed juveniles Average proportion of litter emerged food-addcontrol

Team Lloyd Circuit trapping –all middens within 90 m radius of natal area –until 100 days old – hours of trapping per litter –weight taken at each capture

Individual growth rates food-addcontrol

Average growth rates

Settlement criteria 1. rattled on midden on more than one day 2. trapped at least 3 times at same midden 3. assumption for one rattle during August census – late litters 4. day 100?

Settlement criteria 1. rattled on midden on more than one day 2. trapped at least 3 times at same midden 3. assumption for one rattle during August census – late litters 4. day 100?

Settlement criteria 1. rattled on midden on more than one day 2. trapped at least 3 times at same midden 3. assumption for one rattle during August census – late litters 4. day 100?

Settlement criteria 1. rattled on midden on more than one day 2. trapped at least 3 times at same midden 3. assumption for one rattle during August census – late litters 4. day 100?

Settlement criteria 1. rattled on midden on more than one day 2. trapped at least 3 times at same midden 3. assumption for one rattle during August census – late litters 4. day 100?

Settlement of emerged juveniles 90% settlement in both food-add and control at individual level food-add litters n= 12 control litters n=5

Age at settlement food-addcontrol

Maximum foray distance food-add n = 28 from 12 litters ( ± ) control n= 10 from 5 litters (95.41 ± 37.96) food-add control

Maximum settlement distance food-add n = 24 from 12 litters ( ± ) control n= 9 from 5 litters (76.47 ± 56.56) food-add control

Team Lloyd Territory mapping –juveniles radio-collared –radio-tracked territory boundary –≥ 30 data points

Juvenile territory mapping

Team Lloyd Territory quality index Midden condition ranked midden quality and activity Cone production assessed with cone counts Tree density Spruce bark beetle kill

Survival of settled juveniles

Proportion of total juveniles settled

Too cute not to include