Genetic analysis of the diet of red‐footed boobies (<scp><i>Sula sula</i></scp>) provisioning chicks at Ulupa'u Crater, O'ahu

Donahue, Sarah E.; Adams, Josh; Renshaw, Mark A.; Hyrenbach, K. David

doi:10.1002/aqc.3470

Cited by 8 publications

(14 citation statements)

References 38 publications

(59 reference statements)

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“…While CHSH may ingest some exoparasitic crustaceans attached to flyingfish, they are not known to forage on any other pelagic crustaceans or other taxa that would contribute to mush (Ashmole & Ashmole, 1967; Harrison et al, 1983; Spear et al, 2007). Thus, while digestion leads to the underestimation of the importance of fish in the CHSH diet, the quantification of the mass of mush in the samples can help quantify the magnitude of this bias (Donahue et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

“…The remainder of the sample was passed through a 500 µm sieve. The material retained in the sieve was sorted into categories: “fish,” “squid,” and “mush” (indistinguishable tissue sized >500 µm), following Donahue et al (2021). Everything that passed through the sieve, including the 200 ml of RO water in which the regurgitation was frozen, was transferred to a labeled sterilized container and used as the starting material for DNA metabarcoding analysis.…”

Section: Methodsmentioning

confidence: 99%

“…We used a weighted average freshness (WAF) metric to quantify the degree of digestion of the diet based on the freshness of each prey item per sample on a scale of 1 (fresh and intact prey item) to 3 (highly digested prey item or parts; Donahue et al, 2021). We calculated the WAF of each regurgitation by averaging the freshness value of each individual prey item or their parts, weighted by masses following the formula:

WAF = (\sum false(M_{Pi} * F_{Pi} false) + (M_{Fp} * F_{Fp}) + (M_{Fp} * F_{Fp}) + (M_{m} * F_{m}) / (TM))

where M represents mass and F represents the freshness rank for the different prey constituents: Pi: prey item, Fp: fish parts, Sp: squid parts, m: mush.…”

Section: Methodsmentioning

confidence: 99%

“…Many tropical seabirds also depend on schools of sub‐surface predators that drive prey to the surface and into the air, increasing accessibility to aerial predators (Ashmole & Ashmole, 1967; Ballance et al, 1997; Hebshi et al, 2008). As a result, the diets of tropical seabirds are quite diverse, because these opportunistic predators feed on a variety of shared prey, partitioned by size and vertical position in the water column (Donahue et al, 2021; Harrison et al, 1983; Spear et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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MetaBARFcoding: DNA‐barcoding of regurgitated prey yields insights into Christmas shearwater (Puffinus nativitatis) foraging ecology at Hōlanikū (Kure Atoll), Hawaiʻi

et al. 2021

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Morphological identification of digested prey remains from a generalist predator can be challenging, especially when attempting to match degraded remains to taxonomic keys. DNA techniques, whereby prey is sequenced and matched to large public nucleotide sequence databases, are increasingly being used to augment morphological identification. We used “metaBARFcoding” (DNA metabarcoding) to target a region of the cytochrome c oxidase subunit I (COI) mitochondrial gene to identify prey in highly digested regurgitations from Christmas shearwaters Puffinus nativitatis at Hōlanikū (Kure Atoll). Metabarcoding was used to bulk‐process 92 water samples from regurgitations collected from 2009 to 2017, providing an overview of the seabird's diet. We additionally Sanger‐sequenced 100 prey items from 50 randomly chosen regurgitations to verify that metabarcoding characterized key components of the diet. The metabarcoding technique identified 87 unique taxa from 29 families of fish and squid, spanning diverse taxa, including reef‐associated, pelagic–oceanic, and mesopelagic species. Rare prey (frequency of occurrence ≤5% of samples) constituted 66% of the species richness, demonstrating the highly diverse diet of this generalist predator. Overall, 81% of the families detected in the contemporary diet were previously documented in Christmas shearwater diets from the Northwestern Hawaiian Islands. Our results indicate that metabarcoding the COI region is useful in identifying a wide range of taxa from highly digested regurgitations, thus facilitating this approach to study seabird diets.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

WAF = (\sum false(M_{Pi} * F_{Pi} false) + (M_{Fp} * F_{Fp}) + (M_{Fp} * F_{Fp}) + (M_{m} * F_{m}) / (TM))

where M represents mass and F represents the freshness rank for the different prey constituents: Pi: prey item, Fp: fish parts, Sp: squid parts, m: mush.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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MetaBARFcoding: DNA‐barcoding of regurgitated prey yields insights into Christmas shearwater (Puffinus nativitatis) foraging ecology at Hōlanikū (Kure Atoll), Hawaiʻi

et al. 2021

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“…Prey species were collected in 2018 and 2019 in Cabo Verde waters, by local fishermen operating in the surroundings of Raso Islet or at local fish-markets, between June-October of each year, and therefore are contemporaneous with tracking of BRBO and RFBO. We selected the prey species that could be part of BRBO and RFBOs' diet, according to the data available in the literature for these and other similar taxa [13,[61][62][63]. All prey individuals were measured, weighted, and identified to the lowest possible taxonomic level.…”

Section: Stable Isotope Analysis Of Prey Samplesmentioning

confidence: 99%

Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic

et al. 2021

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In the oligotrophic tropical marine environment resources are usually more patchily distributed and less abundant to top predators. Thus, spatial and trophic competition can emerge, especially between related seabird species belonging to the same ecological guild. Here we studied the foraging ecology of two sympatric species–brown booby (BRBO) Sula leucogaster (breeding) and red-footed boobies (RFBO) Sula sula (non-breeding)–at Raso islet (Cabo Verde), across different seasons. Sexual segregation was only observed during Jun-Oct, when RFBO were present, with larger females BRBO remaining closer to the colonies, while males and RFBO travelled further and exploited different habitats. Overall, species appeared to prefer areas with specific oceanic features, particularly those related with oceanic currents and responsible for enhancing primary productivity in tropical oceanic areas (e.g. Sea Surface Height and Ocean Mixed Layer Thickness). Female BRBOs showed high foraging-site fidelity during the period of sympatry, while exploiting the same prey species as the other birds. However, during the months of co-existence (Jun.-Oct.), isotopic mixing models suggested that female BRBO would consume a higher proportion of epipelagic fish, whereas female RFBO would consume more squid compared to the other birds, possibly due to habitat-specific prey availability and breeding energy-constraints for BRBO. We conclude that divergent parental roles, environmental conditions, habitat preference and competition could be mechanisms simultaneously underlying sexual segregation for BRBO during a period of co-existence, while inter-specific foraging differences appear to be more affected by habitat preference and different breeding stages. These results support previous statements that BRBO can adapt their foraging ecology to different circumstances of environmental conditions and competition, and that marine physical features play an important role in foraging decisions of boobies.

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Variations in inter‐specific and sex‐related niche partitioning in pelagic boobies during their annual cycle

Lerma,

Dehnhard,

Castillo‐Guerrero

et al. 2024

Ecology and Evolution

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Animals that co‐occur in a region (sympatry) may share the same environment (syntopy), and niche differentiation is expected among closely related species competing for resources. The masked booby (Sula dactylatra) and smaller congeneric red‐footed booby (Sula sula) share breeding grounds. In addition to the inter‐specific size difference, females of both species are also larger than the respective males (reversed sexual size dimorphism). Although both boobies consume similar prey, sometimes in mixed‐species flocks, each species and sex may specialize in terms of their diet or foraging habitats. We examined inter‐ and intra‐specific differences in isotopic values (δ13C and δ15N) in these pelagically feeding booby species during the incubation period at Clarion Island, Mexico, to quantify the degrees of inter‐ and intra‐specific niche partitioning throughout the annual cycle. During incubation, both species preyed mainly on flyingfish and squid, but masked boobies had heavier food loads than red‐footed boobies. There was no overlap in isotopic niches between masked and red‐footed boobies during breeding (determined from whole blood), but there was slight overlap during the non‐breeding period (determined from body feathers). Female masked boobies had a higher trophic position than conspecific males during breeding; however, no such pattern was detected in red‐footed boobies. These results provide evidence of inter‐ and intra‐specific niche partitioning in these tropical seabird species, particularly during the breeding period and in the more‐dimorphic species. Our results suggest that these closely related species use different strategies to cope with the same tropical marine environment.

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Genetic analysis of the diet of red‐footed boobies (Sula sula) provisioning chicks at Ulupa'u Crater, O'ahu

Cited by 8 publications

References 38 publications

MetaBARFcoding: DNA‐barcoding of regurgitated prey yields insights into Christmas shearwater (Puffinus nativitatis) foraging ecology at Hōlanikū (Kure Atoll), Hawaiʻi

MetaBARFcoding: DNA‐barcoding of regurgitated prey yields insights into Christmas shearwater (Puffinus nativitatis) foraging ecology at Hōlanikū (Kure Atoll), Hawaiʻi

Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic

Variations in inter‐specific and sex‐related niche partitioning in pelagic boobies during their annual cycle

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