Sampling the Environment and Gathering Information Prospecting

Information gathering about relative habitat quality via prospecting behavior involves sequential visits of potential occupied or nonoccupied patches or sites by an individual

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Experimental manipulation of resident tit density

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Unsuccessful plots

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Figure 10 (Continued)

Figure 11 Combining several sources of information for breeding habitat choice. In the black-legged kittiwake, the fidelity probability of breeders depended on both personal information (i.e., individual reproductive success) and public information (i.e., local reproductive success (RS) of conspecifics on the patch) in the previous year. Individual reproductive success decreases from F2 (high success) down to NF (nest failure: no eggs laid). Local reproductive success: average number of chicks fledged per nesting pair on the patch. Personal and public information significantly interacted. Successful individuals (F2 and F1) were always highly faithful to their breeding patch, while fidelity of early failed individuals (NF and EF) increased with local success. Thus, individuals used both personal and public information to decide whether to emigrate, but prioritize the different sources of information: public information was used only after breeding failure. From Danchin E, BoulinierT, and Massot M (1998) Conspecific reproductive success and breeding habitat selection: Implications for the study of coloniality. Ecology 79: 2415-2428.

that does not currently feed or breed there (called a prospector). Despite the major impact of prospecting on habitat choice, data on prospecting remain fragmentary. Prospectors on breeding patches are usually immature individuals before recruitment, and nonbreeding or unsuccessful adults, which are likely to be looking for a breeding site for the following year. However, the links between prospecting, type of information gathered by prospectors, and subsequent habitat choice are still poorly investigated. Constraints acting on prospecting can however determine which types of information are available to individuals, and thus which habitat choice strategies can evolve. Prospecting may also shape the evolution of life-history traits such as age at first breeding when individuals have to prospect before settling for breeding.

Constraints on Habitat Selection

Habitat choice involves two important steps: (1) deciding whether to leave or stay on the current habitat or patch; (2) if individuals decide to leave, choosing where to settle next. These two sets of decisions may be based on different criteria, and be either independent or linked: individuals may decide to leave before having decided where to settle next; alternatively, they may decide to leave because they have already chosen their next patch. Choices can occur on repeated occasions, and thus be increasingly shaped by personal experience, except for breeding habitat selection in sessile species. Habitat choice is thus a complex process constrained by many

Figure 10 Examples of the use of different types of social information for breeding habitat selection: (I and II) presence of conspecifics, (III) presence of heterospecifics sharing the same needs, (IV and V) local reproductive success of conspecifics. (I) Naive house wren males (Troglodytes aedon) preferred to settle in nest boxes of higher quality (as measured by previous breeding success in the box), but also close to the nearest occupied box. Black squares: boxes located <70 m from the nearest occupied box (open squares for >70 m). (II) Immigration rate of new breeders in a patch strongly positively increased with patch breeding density in the previous year, for both (a) experienced (>2 years old) and (b) naive (yearling) collared flycatchers. (III) The number of migrant passerine bird species and densities of migrant individuals were lower in patches where the density of heterospecific resident tit (Parus) species was decreased (REM) by removing individuals than in patches where it was increased (ADD) by releasing them. (IV) Immigration rate of collared flycatcher breeders was higher in patches where the mean number of fledglings had been increased locally (by adding nestlings - patches I) in the previous year compared to control (C1 and C2) patches (unchanged mean fledgling number), and higher in control patches compared to patches where the mean fledgling number had been decreased locally (by removing nestlings - patches D). (V) In the black-legged kittiwake, (a) prospecting and (b) nest attendance by failed breeders were higher on patches where local success was unchanged (black dots) than where it had been experimentally decreased by removing eggs (open dots), and, in the following year, (c) failed breeders were more likely to return to breed on the same patch in patches where success was unchanged (black bar) compared to decreased patches (open bar). (I) From Muller KL, Stamps JA, Krishnan VV, and Willits NH (1997) The effects of conspecific attraction and habitat quality on habitat selection in territorial birds (Troglodytes aedon). American Naturalist 150: 650-661. (II) From Doligez B, Part T, Danchin E, Clobert J, and Gustafsson L (2004) Availability and use of public information and conspecific density for settlement decisions in the collared flycatcher. Journal of Animal Ecology 73: 75-87. (III) From Forsman JT, Monkkonen M, Helle P, and Inkeroinen J (1998) Heterospecific attraction and food resources in migrants' breeding patch selection in northern boreal forest. Oecologia 115: 278-286. (IV) Reproduced from Doligez B, Danchin E, and Clobert J (2002) Public information and breeding habitat selection in a wild bird population. Science 297: 1168-1170, with permission from AAAS. (V) From Boulinier T, Yoccoz NG, McCoy KD, Erikstad KE, and Tveraa T (2002) Testing the effect of conspecific reproductive success on dispersal and recruitment decisions in a colonial bird: Design issues. Journal of Applied Statistics 29: 509-520.

parameters linked to: (1) species characteristics, in particular cognitive (spatial and temporal memory) and movement capacities (maximal movement rate or distance, especially when individuals have to travel across unsuitable habitat - arrows in Figure 1); (2) species life-history strategy and tradeoffs involved (investment in different activities, in particular prospecting vs. breeding; tradeoffs in choosing multiusage sites, in particular year-round territories); (3) individuals' characteristics and interindividual differences in the ability to exploit the environment (phenotype- or genotype-environment interactions), in habitat preferences (through imprinting or habitat training due, for example, to acquired parasite resistance), or in selective pressures (e.g., sexual selection depending on individual's sex); and (4) environment variation (e.g., temporal predictability, spatial variation patterns).

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