Exceptionally high apparent adult survival in three tropical species of plovers in Madagascar

Abstract

Adult survival is a key component of population dynamics, and understanding variation in and the drivers of adult survival rates and longevity is critical for ecological and evolutionary studies, as well as for conservation biology and practice. Tropical species of landbirds are often selected to have higher adult survival due to high nest predation rates, but it is unclear if the same patterns occur in other avian lineages with different life history strategies. Here, we investigate adult survival of three sympatrically breeding species of shorebirds in south-west Madagascar: the endemic and endangered Madagascar plover Charadrius thoracicus and two more widely distributed African species: the white-fronted plover C. marginatus and the Kittlitz's plover C. pecuarius. Using mark-recapture data from 1843 individuals breeding at an intensely monitored saltmarsh over a 13-year period, we estimated annual rates of apparent survival (φ) corrected for encounter probability. Adult apparent survival rates were high for all three species (mean ± SE): Madagascar (φ = 0.899 ± 0.010) and whitefronted plovers (φ = 0.923 ± 0.008). Kittlitz's plovers showed a difference between the first (φ 1 = 0.719 ± 0.026) and subsequent transitions (φ 2+ = 0.892 ± 0.014), suggesting that transient breeders are common in this species. For birds first captured as adults, these survival estimates translate to life expectancies of 9.72 (±1.11) years in Kittlitz's plovers, 9.36 (±0.98) years in Madagascar plovers and 12.48 (±1.32) in white-fronted plovers. We hypothesise that a long lifespan could be an adaptation arising from the unique climatic pressures on the island of Madagascar that would otherwise lead to reduced fitness. However, long lifespans may not sufficiently compensate for a reduction in breeding opportunities due to possible climatic disruption in the future. Consequently, at least two of these plover species seem vulnerable to ongoing habitat destruction and changing climate cycles.

Climatic variation influences annual survival of an island‐breeding tropical shorebird

“…Our estimate of apparent annual adult survival of Φ 2+ = 0.849 ± 0.013 for Kentish plovers in Maio is relatively high compared to other populations at mainland locations as estimates of apparent adult survival for mainland populations of Kentish and snowy plover (a close relative of the Kentish plover), range from 0.61 to 0.64 in the Netherlands (Foppen et al 2006), 0.64 ± 0.01 SE in Turkey (Sandercock et al 2005), 0.687 ± 0.039 SE in Utah (Paton 1994), 0.756 ± 0.05 SE in Spain (Garcias and Tavecchia 2018), and up to 0.720–0.759 for a population in coastal California (Stenzel et al 2011). Our estimate was also higher than another population of Kentish plovers in the Canary Islands (0.68, Tejera et al 2022) but was comparable to survival rates of other tropical island populations of Charadrius plovers from Madagascar (0.892–0.923, Jones et al 2022). High annual survival rates are also a common feature among endemic songbirds elsewhere in the island archipelagos of Macaronesia (Illera and Díaz 2008, Monticelli et al 2010, Dierickx et al 2019).…”

“…Adult survival tends to be higher in island populations compared to mainland populations, possibly due to milder climate on islands that are buffered by oceanic conditions and fewer parasites or predators (Beauchamp 2021). In addition, life history theory predicts that in tropical regions smaller clutch sizes are balanced with higher adult survival compared to the north temperate populations that have larger clutch sizes and lower adult survival (Martin 1996, Ghalambor and Martin 2001, Muñoz et al 2018, Jones et al 2022).…”

“…We used 15 years of capture–recapture data to estimate juvenile and adult survival of individuals ringed as chicks or as male and female adult Kentish plovers (Tico 2011, Carmona 2016, Engel et al 2020, McDonald et al 2020). Charadrius plovers are well‐studied model systems in population ecology (Colwell and Haig 2019, Székely 2019) so that here we can compare the Maio demographic parameters with other Charadrius plovers that breed on other islands or on mainland (Stenzel et al 1994, Sandercock et al 2005, Mullin et al 2010, Windsor 2020, Jones et al 2022, Tejera et al 2022).…”

Annual captures and low apparent survival rates in two tit species in western Hungary

“…Additionally, the number of "potential transients" (Ryu et al 2016) was very low in the breeding and unknown in migration seasons: therefore, the data for all captured adults were pooled. The survival probabilities of passerines at a particular site are frequently analysed by using capture-recapture models: the Cormack-Jolly-Seber (CJS) formula is used most often (Lebreton et al 1992, Naef-Daenzer et al 2001, Williams et al 2002, Greńo et al 2008, Jones et al 2021. In the CJS model, the probability of encounter (p) is explicitly modelled in order to correct possible biases in survival estimates (Jankowiak et al 2016).…”

“…In order to understand the causes of population dynamics, detailed demographic information is required. In bird populations, survival (Tinbergen & Boerlijst 1990, Adriaensen et al 1998, dispersal and site fidelity (Both et al 2012, Mátrai et al 2012 are essential components for understanding the causes of population growth and decline (Jones et al 2021). Survival, or fitness, may depend on the age, sex, behaviour, habitat and seasonal occurrence of the tits (Dhondt 1979, Horak & Lebreton 2008, Class et al 2014.…”