1. Friday March 20 th going out for an extended lab time, no lecture CHAPTER 11: AVIAN SOCIAL BEHAVIOR Pair of female Northern Cardinals (Cardinalis cardinalis) rumbling

2. This chapter focuses more on non-breeding social interactions  Flocking species and acquisition of status in flocks  Foraging or roosting spots  Territoriality  Defending resources from others Interactions with other species entirely  Food, territory, other resources SOCIAL BEHAVIOR A female Eastern Bluebird (Sialia sialis) attacking a female House Sparrow (Passer domesticus) over a nest box

3. SOCIAL BEHAVIOR Individual spacing and ‘personal space’ important

4. Territoriality  Defending a fixed area for your personal use  Can be temporary or longer term  Contains resources that you use exclusively  Food, nest sites, roosting sites, safe areas from predators May defend from just your own species, may defend from others as well  Neighbors and floaters – the threat differs in many ways  Breeding territories, wintering territories, general purpose territories Defense or announcement of ownership by songs, calls, or displays SOCIAL BEHAVIOR

5. Territory distribution of Northern Cardinals (Cardinalis cardinalis) at Aullwood Audubon Center, Dayton, OH Typical song posture of a male cardinal

6. Benefits to territory defense  Assuring a limited resource is available Costs to territory defense  Must expend energy to keep your resource safe  Chasing, fighting, displaying Payoff, protecting the energy source means energy to pay back expense SOCIAL BEHAVIOR Golden-winged Sunbird (Nectarinia reichenowi)

7. SOCIAL BEHAVIOR Defending a territory from competitors, and defending the optimal size territory, is only feasible when the costs of doing so (energy, potential injury) are outweighed by the benefits (food, safety) When costs are too great territory is either abandoned (become non-territorial) or allowed to shrink (give up some until defense is feasible)

8. SOCIAL BEHAVIOR Territory size required varies with species and with resource being used Larger species typically need more than smaller species (general space) Predators need more area than herbivores (energy dynamics) Quality of the resource on the territory can also determine size Archilochus colubris

9. SOCIAL BEHAVIOR Acorn Woodpecker (Melanerpes formicivorus) granaries are a valuable resource, strongly defended by a group.

10.  Floaters and neighbors are always looking to take territory  A territory owner has precedence over an intruder  Owner knows the value and knows the lay of the land  Experimentally remove an owner and usurpers fight to remain based on how long they’ve occupied territory  Neighbors will take some of what’s yours if that is allowed  Long-term territoriality, boundaries are established  ‘Dear Enemy’ – ‘I know you and what you can do, you cannot steal from me’  ‘Nasty Neighbor’ – ‘I know you and what you can do and what you have, I can take it from you as you’re weak’ SOCIAL BEHAVIOR

11. Within flocking species dominance status can be important  Better access to food  Better access to safety  Better access to future mates  Better access to future territories There are costs associated with this  Some species, dominants have high corticosterone levels SOCIAL BEHAVIOR Red Junglefowl (Gallus gallus) females establish ‘pecking orders’ among their flocks for access to food and mates

12.  Social interactions can be what keeps order in groups and what keeps your resources yours, but  Energy it takes to fight  Costs due to injury – can be very expensive (death the most expensive)  There must be other ways to communicate besides just jumping right to the attack! SOCIAL BEHAVIOR

13. Harris's Sparrow, Zonotrichia querula “Stud” Not so much a ‘Stud’ Physical appearance, ornamentation, can be used to quickly identify who is likely to be dominant and who isn’t. Ornament expression typically co-varies with age, quality, sex, or steroid hormones in such a way as to reliably indicate who is who.

14. Experimental modification of ornaments and status  Harris’s Sparrows  Only with implant of T could non-studs dyed to look like studs succeed  House Sparrows  Birds dyed to look dominant succeeded for a bit, then were tested  Northern Cardinals  Alteration of red didn’t change flock status, something other being used? SOCIAL BEHAVIOR A pale cardinal held his own even if he was super red originally

15. SOCIAL BEHAVIOR Spotted Antbird (Hylophylax naevioides) Bicolored Antbird (Gymnopithys leucaspis) Ocellated Antbird (Phaenostictus mcleannani) Benefits of dominance within flocks, either of a single species or mixed species, that you get the best food. Not just ornaments but sheer physical size can be important

16. SOCIAL BEHAVIOR Large Ocellated Antbirds (~50g) take precedent at the center of Army Ant swarms, here is the best insect foraging opportunities White-plumed Antbird (Pithys albifrons)

17.  Aggressive (agonistic) behavior  A physical interaction is going to ensue, one will win and one will not  If ornaments that co-vary with status not enough, fights may ensue  Typically birds of similar status within flocks, or of similar ornamentation  Often a stereotypical set of behaviors or postures to show intent  Threat, displacement, attack/chase  Bird that isn’t winning or isn’t escalating has appeasement display SOCIAL BEHAVIOR

18. This is what displays are trying to circumvent, here two male Yellow Warblers (Dendroica petechia) really battle it out Don’t be fooled by group selection arguments, avoiding this is good for both the loser and the winner.

19. SOCIAL BEHAVIOR Steller's Jay (Cyanocitta stelleri) Not ready to rumble, trying to diffuse the situation Peeved and ready to do something about it

20. SOCIAL BEHAVIOR Ultimate attack stance in Northern Cardinals (Cardinalis cardinalis)

21.  Surprisingly some aspects of courtship have aggressive components  Some suggest females incite males to fight to pick the best  Males may need to overcome gut reaction to a conspecific  A male could be mistakenly be trying to defend against an intruding female  Mate has disappeared very recently SOCIAL BEHAVIOR

22.  Aggressive behavior makes one think of males, and males have been focused on  Females are aggressive too  Status in a flock/group  Territory boundaries  Access to males  Defense of nesting resources SOCIAL BEHAVIOR

23.  Flocks – groups of birds, can be small (6 or so) can be huge (millions of individuals)  Can be all the same species, can be comprised of multiple species – more later  This has costs and benefits  Benefits  Safety in numbers, ease in finding food (work of off producers), more time devoted to foraging  Costs  Someone takes your food (scrounger), constant fighting for dominance, increased disease transmission, food might not be super-abundant SOCIAL BEHAVIOR

24. Red-billed Quelea (Quelea quelea) flocks are enormous; promotes safety, and can manipulate the scrounger/producer system

25. SOCIAL BEHAVIOR Young Common Ravens (Corvus corax) use flocks for information sharing and to gang up for resource acquisition

26. SOCIAL BEHAVIOR Predator Being in a flock can help you avoid predation (dilution effect, confusion effect, and more eyes on the look-out)

27. SOCIAL BEHAVIOR European (Common?) Starlings (Sturnus vulgarus) alter their behavior when they cannot easily see others, shows the benefits of associating in flock

28. SOCIAL BEHAVIOR Multiple factors go into decisions concerning flock size, if dynamics around the flock change the optimal inclusion of more or less individuals will alter as well. Notice the cost of fighting with others over access to resources.

29.  Mixed species flocks – lots of species moving together  Why do this?  Some cases, the resource you’re after forces you together – antbird species following army ants  Rare or territorial species may not have enough of their own around, joining with others a must (safety, better foraging)  Surprisingly social signals are interpretable across species groups  Appearance and behaviors associated with dominance cross species boundaries  Often habitual associations lead to similar appearances SOCIAL BEHAVIOR

30.  Some cases individuals live or associate in super groups  Colony nesters – enormous groups nesting near each other  ~13% of species do this, primarily seabirds  Shortage of safe nesting spots, everyone congregates where it’s best/safest  Communal roosting  Large groups offer safety – intimidating to predators and many eyes on the watch  Large groups offer information – ‘Who ate well today, perhaps I’ll follow them tomorrow’  So many together, if sheltered, may reduce energy demands for thermoregulation  May be easier to find a mate in the group  But, energy spent on aggressive interactions over dominance and individual spacing; disease transmission SOCIAL BEHAVIOR

31. Royal Tern (Thalasseus maximus) nesting colony, just area around body ‘secured’

32. SOCIAL BEHAVIOR Not really a communal roost here, but crowding can have detrimental impacts. Here, birds on the bottom of the piles have been known to suffocate and if one individual is sick, everyone is going to get it.