1. Why male orangutans do not kill infants

   • Lydia H. Beaudrot
   • Sonya M. Kahlenberg
   • Andrew J. Marshall

   Review Open access 21 July 2009 Pages: 1549 - 1562

   

2. Body size and reserve protection affect flight initiation distance in parrotfishes

   • Kiyoko M. Gotanda
   • Katrine Turgeon
   • Donald L. Kramer

   Original Paper 31 March 2009 Pages: 1563 - 1572

   

3. Male mating preference is associated with risk of pre-copulatory cannibalism in a socially polymorphic spider

   • Jonathan N. Pruitt
   • Susan E. Riechert

   Original Paper 24 March 2009 Pages: 1573 - 1580

   

4. On the consequences of aggressive male mate-locating behaviour and micro-climate for female host plant use in the butterfly Lycaena hippothoe

   • Camille Turlure
   • Hans Van Dyck

   Original Paper 24 March 2009 Pages: 1581 - 1591

   

5. Movement signal choreography unaffected by receiver distance in the Australian Jacky lizard, Amphibolurus muricatus

   • Richard A. Peters
   • Simon J. Allen

   Original Paper 24 March 2009 Pages: 1593 - 1602

   

6. Utilization of a new host in the screaming cowbird Molothrus rufoaxillaris, a host specialist brood parasite: host switch or host acquisition?

   • Bettina Mahler
   • Yanina Sarquis Adamson
   • Juan C. Reboreda

   Original Paper 31 March 2009 Pages: 1603 - 1608

   

7. Trans-Sahara migrants select flight altitudes to minimize energy costs rather than water loss

   • Heiko Schmaljohann
   • Felix Liechti
   • Bruno Bruderer

   Original Paper 25 March 2009 Pages: 1609 - 1619

   

8. Nursing of own and foster offspring by Utah prairie dogs (Cynomys parvidens)

   • John L. Hoogland

   Original Paper 22 April 2009 Pages: 1621 - 1634

   

9. Hierarchical perception of fertility signals and nestmate recognition cues in two dolichoderine ants

   • Laurent Cournault
   • Jean-Christophe de Biseau

   Original Paper 09 May 2009 Pages: 1635 - 1641

   

10. Resource distributions affect social learning on multiple timescales

    • Daniel J. van der Post
    • Bas Ursem
    • Paulien Hogeweg

    Original Paper Open access 30 May 2009 Pages: 1643 - 1658

    

11. Helpers and egg investment in the cooperatively breeding acorn woodpecker: testing the concealed helper effects hypothesis

    • Walter D. Koenig
    • Eric L. Walters
    • Joseph Haydock

    Original Paper Open access 20 May 2009 Pages: 1659 - 1665

    

12. The interplay between genetic and environmental effects on colony insularity in the clonal invasive little fire ant Wasmannia auropunctata

    • Merav Vonshak
    • Tamar Dayan
    • Abraham Hefetz

    Original Paper 23 May 2009 Pages: 1667 - 1677

    

13. Sperm viability staining in ecology and evolution: potential pitfalls

    • Luke Holman

    Methods 07 July 2009 Pages: 1679 - 1688

    

14. Eigenbehaviors: identifying structure in routine

    • Nathan Eagle
    • Alex Sandy Pentland

    Erratum 21 July 2009 Pages: 1689 - 1689

15. Disentangling the effects of group size and density on shoaling decisions of three-spined sticklebacks (Gasterosteus aculeatus)

    • Joachim G. Frommen
    • Meike Hiermes
    • Theo C. M. Bakker

    Erratum 22 July 2009 Pages: 1691 - 1691