Does group size influence territory size and overlap Does group size influence territory size and overlap in a cooperative breeder, an experimental population in a cooperative breeder, an experimental population

of Buff-throated Partridge?of Buff-throated Partridge? • Nan YangNan Yang11, K. Zhang, K. Zhang11, J.H Ran, J.H Ran11, H. Lloyd, H. Lloyd2 2

& B.S Yue& B.S Yue11

1 College of Life Sciences, Sichuan University, Chengdu 610064, China;

2World Pheasant Association, Close House Estate, Heddon on the Wall, Newcastle upon Tyne, NE15 0HT, United Kingdom;

*corresponding author: rjhong-01@163.com

Medium-sizedMedium-sized

Endemic to ChinaEndemic to China

VulnerableVulnerable

Buff-throated Partridge (Buff-throated Partridge (BTPABTPA)) Tetraophasis szechenyii

Distribution areasMainly distributed in high altitude habitatsMainly distributed in high altitude habitatsin Western China.in Western China. southwest Sichuan

south Qinghai northwest Yunnan and southeast Tibet

The typical habitat of BTPA is mixed conifer forests, alpine shrub and tundra above the tree-line at the altitude between 3300 to 5000 m.

• Little is known about mating system, according to Little is known about mating system, according to previous observations it is presumed to be a previous observations it is presumed to be a monogamous or polygynous species, but our study monogamous or polygynous species, but our study suggested this species turn out to be a suggested this species turn out to be a COOPERATIVE BREEDING species.

Cooperative behavior• Living in family groups, roost together • Group size: 2.81 ± 0.09 (n = 68) • 65% (44/68) breeding pairs have up to three helpers • Don’t form big winter flock• All helpers exhibited brooding, vigilance and territorial

display

3♂1♀, +3Juveniles

3♂2♀, lasted 2 years.≧

Cooperative breeding

Environmental constraints

Cooperative breeding

Arise Rare in Galliformes

Larger groups Better & high-quality territory

Greater reproduction

Conflict of interest betweengroup size & composition

Exist

Inhabit

Little knowledge exist

Year-round residents

Objectives• Determine seasonal territory size and degree

of overlap between neighbors • Identify relationship between group size and

territory size and overlap

• Using an experimental population, partially habituated through supplemental feeding

• Implications for studying ‘truly wild’ populations

Study area and habitat types

Pamuling Tibetan Monastery

●

Pamuling Mountains in southwest of Sichuan from 2006 to 2009Ranged:3900-4200Snow covered: November to April

The main habitat types

Characterized by a series of dark coniferous forest, oak thickets, rhododendron shrubs and meadow.

Hollyleaf alpine Oak Forest

Alpine Meadow

Flaky Fir Forest

Violet-purple Rhododendron Shrub

Pamuling Monastery

Territory sizeWe defined territories as the area that the BTPA occupy and defend against other groups for the purpose of reproduction, and providing foraging resources for all breeding individuals, nestlings, and other members.

Methods• Locating groups and data collections: direct tracking of

colour-marked individuals

• Data analysis: using SPSS for windows release 11.0; All tests were two-tailed (α =0.05). Mean values are given ± the standard error (SE)

• Seasonal divisions: breeding season and non-breeding season

• Territory size and overlap: BIOTAS software v.2.0 with 100% Minimum Convex Polygon

ResultsTable 1. Territory size (100% Minimum Convex Polygon ) for a experimental

population of BTPA direct tracked from March 2007 to July 2009.

• Territory size was independent of group size in breeding season and non-breeding season ( F3,17=0.1, P=0.96; F2,11=2.5, P=0.132).

• All territory sizes did not vary during the duration of study (F2,17=1.7, P=0.22; F1,11=4.3, P=0.07, respectively).

Table 2. Percentage overlap in 100% Minimum Convex Polygon territory for neighboring groups in BTPA.

• The difference in territory overlap between breeding pairs with and without helpers was significant in the breeding season (ANOVA, F3,17=4.2, P=0.024).

• But group size did not affect territory overlap in the non-breeding season (ANOVA, F3,24=0.8, P=0.516).

Discussion • Main factors associated with cooperative breeding in

BTPA:Severe/harsh climate (unpredictable weather)?Direct benefits (e.g. increase food access and survival, enhanced breeding experience)?Lack of breeding habitat or vacant territories?

15 days

3 days

• Possible factors constraining ranging behaviors in BTPA:

• Forage and roost together, take active care and guard the nest and chicks

• Predation and neighbor competition pressure?

We found that:

• Group size does not affect territory size in this Group size does not affect territory size in this experimental populationexperimental population

• Food not limited?

• Effect of supplementary feeding?

• Currently examining correlations between territories, home range, roost sites and supplemental feeding

Other studies:

• Breeding Pied Wagtails permit ‘satellite’ (non-breeding) wagtails to share and defend territory when food is abundant

• Direct tracking data of Tibetan Eared-pheasant Crossoptilon harmani showed that spatial location of foraging and roosting sites were only determinant of home range size

• Food availability at roosting sites (on the ground) for Tibetan Eared-Pheasant was lower than at foraging sites.

• Cooperative groups had smaller territory overlap than pairs without helpers in breeding season:

• Energy and nutrient requirements?• Reduce predation risk and competition?

• Larger territory overlap in non-breeding season:

• Increase encounter rate and reduce inbreeding?

Acknowledgements

Dr. Philip McGowan Dr. Ying Wang Dr. Siegfried Klaus Wangqing Li Pamuling MonasteryForestry Bureau of Yajiang County

Thank Thank you!!!you!!!