Nest-type associated microclimatic conditions as potential drivers of ectoparasite infestations in African penguin nests

Abstract

Nest design and characteristics can influence the microclimatic conditions in the nest. Nest-dwelling ectoparasites are sensitive to temperature and moisture and as such the conditions in the nest can influence parasite infestations. The endangered African penguin (Spheniscus demersus) breeds in different nest types and as yet little is known with regard to the microclimate and parasite infestation within these nests. This study characterized the microclimatic conditions in natural open, natural covered (with vegetation) and artificial nests, and assessed the relationship between nest characteristics (type, age, distance from the coast, orientation and entrance opening) and in-nest ectoparasite infestations and the health of African penguins in Stony Point, South Africa. Penguins (50 adults and 192 chicks) and their nests (n = 308) were sampled in 2016 and 2017. Soil temperature was higher in artificial than in natural nests, and soil and nest material moisture was lower in artificial and natural covered nests than natural open. Ectoparasite infestations were higher under warmer and drier conditions, in artificial nests and nests near the coastline. Penguin (adult and chick) body mass and chick body condition were lower in warmer nests and total plasma protein (in adults and checks) was lower in drier nests. Given the potential adverse effects of ectoparasites on host species, it is recommended that conservation agencies implement a monitoring programme to assess the ectoparasite infestation in artificial nests across multiple colonies. This information will facilitate a more holistic penguin conservation management plan that may prevent further detrimental effects on this endangered penguin species.

Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa

“…2007; Sherley et al . 2012; Pichegru 2013; Espinaze et al 2020) and Lei et al (2014) recommended the use of cement nests, which at the time showed higher breeding success than surface nests or fibreglass artificial nests in African Penguins breeding on Bird Island. However, these cement nests still posed a threat to penguins because of the high temperatures that they reached (above 50°C on occasions).…”

“…As part of this plan, managing authorities intervened by installing artificial nests at various breeding sites to protect penguins from extreme weather events and predation (Pichegru 2013). Several versions of these artificial nests have been tried with variable success (Kemper et al 2007;Sherley et al 2012;Pichegru 2013;Espinaze et al 2020) and Lei et al (2014) recommended the use of cement nests, which at the time showed higher breeding success than surface nests or fibreglass artificial nests in African Penguins breeding on Bird Island. However, these cement nests still posed a threat to penguins because of the high temperatures that they reached (above 50°C on occasions).…”

“…Future studies should also consider the potential impact of parasites. For example, even though ceramic nests may provide an ideal microclimate for breeding, parasites may build up in the nests, forcing the birds to move breeding sites (sensu Espinaze et al 2020), resulting in a decline in usage of these nest types in future. This type of approach would facilitate a more effective site-specific management plan, especially when combined with data for breeding success.…”

“…Although nest boxes are not without problems related to design, placement, and parasites (Møller 1989, Butler et al . 2009, Lambrechts et al 2012, Espinaze et al 2020) for example, they are generally an effective tool to facilitate a population recovery. Nest boxes were first installed on Bird Island, Algoa Bay, Eastern Cape, South Africa (33°50’S, 26°17’E) in 2009 to promote population growth in African Penguins (refer to Pichegru 2013 for full details).…”

“…These artificial housing units, hereafter nest boxes, provide shelter from predators and buffer climate variability, and have proven to be a valuable conservation measure for seabirds (Bolton et al 2004, Carlile et al 2012, Libois et al 2012) and many other animals (see Beyer and Goldingay 2006, Goldingay and Stevens 2009, Lambrechts et al 2012, Rueegger 2016. Although nest boxes are not without problems related to design, placement, and parasites (Møller 1989, Butler et al 2009, Lambrechts et al 2012, Espinaze et al 2020 for example, they are generally an effective tool to facilitate a population recovery. Nest boxes were first installed on Bird Island, Algoa Bay, Eastern Cape, South Africa (33°50'S, 26°17'E) in 2009 to promote population growth in African Penguins (refer to Pichegru 2013 for full details).…”