Survival Rates of Adult European Grebes (Podicipedidae)

Abt, Kai; Konter, André

doi:10.5253/078.097.0307

Cited by 3 publications

(2 citation statements)

References 18 publications

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“…Only small passerine birds, like sparrows or tits, are likely to have a maximum annual λ of 1.5 without immigration, whereas for gulls, geese, cormorants, the maximum annual λ would be 1.2 or lower (see also Doxa et al 2013). For a species like a Black-necked/Eared Grebe Podiceps nigricollis , with an annual adult survival rate around 0.7, and 1-2 fledglings per year per pair (Jehl et al 2002, Abt and Konter 2009), an annual multiplication rate of 1.5 therefore is unlikely to be achieved by the sole recruitment of locally born birds. There must have been a major contribution of immigration of new breeders.…”

Section: Discussionmentioning

confidence: 99%

Status of the Northern Silvery Grebe Podiceps juninensis in the northern Andes: recent changes in distribution, population trends and conservation needs

Guevara¹,

Santander²,

Soria³

et al. 2016

Bird Conservation International

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SummaryThe Northern Silvery Grebe Podiceps juninensis is an aquatic bird species considered Vulnerable to extinction in Ecuador and Endangered in Colombia. Globally the species is considered Near Threatened. Herein we report recent changes in distribution and population trends for the subpopulation in the northern Andes (Ecuador, Colombia), which is small and isolated. The Northern Silvery Grebe has undergone two documented extirpations, and at least one colonisation event, over the last three decades. More than 90% of the subpopulation relies on two wetlands, La Mica and Colta lakes in Ecuador, with the latter facing an accelerated sedimentation process which jeopardizes the fate of the wetland, and the species, in the mid-term. The population of La Mica lost 80% of its birds in 2000 after the damming of the lake, but then remained stable over our census period (2004–2013). In contrast, the Colta population results from a recent colonisation in the early 2000s, and has experienced an exponential growth since then (annual population multiplication rate: 1.464). The growth of this population is so fast that it must include an important contribution of immigrants. The temporal coincidence between the drop in population size at lake La Mica and the colonisation of lake Colta suggests that the Colta population was founded by immigrants from La Mica. Finally, the absence of current reports of the species at wetlands in Colombia suggests that the species remains at very low numbers, bolstering the shrinkage in northern distribution.

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Section: Discussionmentioning

confidence: 99%

Status of the Northern Silvery Grebe Podiceps juninensis in the northern Andes: recent changes in distribution, population trends and conservation needs

Guevara¹,

Santander²,

Soria³

et al. 2016

Bird Conservation International

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“…In accordance with this finding, it is in relatively long-lived species where such displays appear common. For example, the two species illustrated in figure 1 with the most obvious mutual displays are the great crested grebe, with an annual adult mortality rate estimated at about 0.25 [28] and the yellow-legged gull (Larus michahellis), with an estimated adult mortality of less than 0.15 [29]. Thus, evolution by mutual mate stimulation appears particularly likely in those longlived, essentially monomorphic, pair-bonding species, which are exactly those species where sexual selection appears to be particularly unlikely [6].…”

Section: Discussionmentioning

confidence: 99%

Evolution of displays within the pair bond

2013

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Although sexual selection is an important cause of display evolution, in socially monogamous species (e.g. many birds), displays continue after formation of the pair bond. Here, we consider that these displays evolve because they stimulate the partner to increase investment in offspring. Our study is motivated by elaborate mutual displays in species that are largely monomorphic and have long-term pair bonds (e.g. the great crested grebe, Podiceps cristatus) and by many empirical results evidencing that display manipulation affects parental investment. Using population genetic models, we show that a necessary condition for the permanent establishment of mutual displays in the pair bond is that the benefit of investment by the pair is more than twice that resulting from investment by a single individual. Pre-existing biases to respond to displays by increased investment are a necessary component of display evolution. We also consider examples where one sex (e.g. males) stimulates increased investment in offspring by the other sex. Here, display and additional investment cannot evolve permanently, but can increase and linger at high frequency for a long time before loss. We discuss how such transient effects may lead to the evolution of permanent displays as a result of evolution at additional loci.

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