1. Avian Brood Parasitism: Variation in Host Response
Bayley Slack

2. What is Brood Parasitism?
Obligate vs. Facultative
Inter-specific vs. Intra-specific

3. Cuckoos & Cowbirds

4. Host vs. Parasite Parasites benefit, at the cost of the host
Co-evolutionary arms race often occurs between the host and the parasite

5. Frontline Defenses Mobbing-alarm calls, physical attacks 2 purposes
- prevent parasitic egg laying
- prevent egg removal/destruction by parasite

6. Egg Rejection Discrimination among eggs Two forms
- ejecting parasitic egg from nest
-abandoning entire nest
How do hosts know when to reject?
- visual cues (spotting, size, brightness,etc.)
- egg arrangement

7. Spottiswoode, C. N. , and Stevens, M. (2011)
Spottiswoode, C.N., and Stevens, M. (2011). How to evade a coevolving brood parasite: egg discrimination versus egg variability as host defences. Proc Biol Sci 278, 3566–3573.

8. Polačiková, L. , Takasu, F. , Stokke, B. G. , Moksnes, A. , Røskaft, E
Polačiková, L., Takasu, F., Stokke, B.G., Moksnes, A., Røskaft, E., Cassey, P., Hauber, M.E., and Grim, T. (2013). Egg arrangement in avian clutches covaries with the rejection of foreign eggs. Anim Cogn 16, 819–828.

9. Chick Rejection Less common than egg rejection 2 forms:
Physically remove chick
Abandon entire nest
How do host know when to reject?
-amount of parental care required
-incubation call as password

10. Influences on Host Response
Variety of defenses seen in hosts
Influenced by:
-parasitic pressure
-parasitic species
-host personality/behavior
Host that do not defend:
-evolutionary lag
-evolutionary equilibrium

11. To Conclude…
Brood parasitism benefits the parasite, at the cost of the host
Host use variety of defenses to avoid parasitism
Which defense is used, and when, is dependent upon the specific situation
Some hosts choose to accept parasitism