Gull Populations Research Articles

Age-related presence and genetic diversity of Campylobacter spp. in young and adult yellow-legged gulls (Larus michahellis) in Croatia.

The epidemiology of Campylobacter species in wild birds is still poorly understood. This study describes the occurrence and genetic diversity of Campylobacter in adult and nestlings of yellow-legged gulls, highlighting differences between breeding locations. The gulls were captured in Croatia between 2021 and 2023. A cloacal swab was taken from each individual and tested for the presence of Campylobacter. Isolated Campylobacter species were genotyped using the multilocus sequence typing (MLST) method. A total of 1071 gulls were captured and sampled, of which 152 samples were identified as Campylobacter species, with Campylobacter jejuni (9.90%) being the most frequently isolated bacterium, followed by Campylobacter lari (3.36%) and Campylobacter coli (0.93%). Complete sequence type (ST) profiles were generated for 141 isolates: 100 C. jejuni, 33 C. lari, and 8 C. coli. A significant difference in the occurrence of positive Campylobacter species was found depending on the sampling sites, while both sampling site and age were significant for the occurrence of C. jejuni. Adults and nestlings showed high genetic diversity for C. jejuni and C. lari, and there were no significant differences between strains isolated from adults and nestlings or between sites, suggesting a high genotype flow in the studied gull population.

Revisiting the Past: Historical Status of Breeding Ring-billed and California Gulls in the Klamath Basin, Oregon

Three summaries of the historical and recent status of breeding Ring-billed (Larus delawarensis) and California (L. californicus) gulls in Oregon mention just two colony sites in the Klamath Basin—Upper Klamath Lake and Spring Lake—and lack numerical data for individual colonies. Nevertheless, nesting of gulls at Lower Klamath Lake before its water source was cut off in 1917 is well documented. Egg-set records, published literature, and archived field notes attest to nesting of both species before 1954 at two additional sites in the Klamath Basin, the Link and Klamath rivers. The largest known colonies up to that time were at Lower Klamath Lake (~2000 pairs, perhaps many more) and along the Klamath River below the town of Klamath Falls (~2000 pairs). Gulls no longer nest at these five sites, but, since at least 2000, they have nested intermittently at Swan Lake and Gerber Reservoir. Though Gabrielson and Jewett (1940) considered the California Gull more abundant in southeastern Oregon than the Ring-billed, egg-collectors’ data from 1926 to 1953 suggest the opposite, as in northeastern California. The California Gull may have been the more numerous of the two in the Klamath Basin when nesting and foraging habitat was dominated by wetlands, but the drying of Lower Klamath Lake and the great expansion of irrigated agriculture starting in the 1920s may have favored the Ring-billed. Trends in the Klamath Basin’s gull populations are unclear, but much nesting habitat has been lost. Documentation of the historical record of nesting gulls and other waterbirds is critical, as conservation efforts typically aim at restoring populations to some historical baseline, which can gradually shift lower with further declines and successive generations accepting a new status quo.

Insights into trophic interactions: DNA metabarcoding reveals species composition in black-tailed gull fecal samples in coastal environments of South Korea.

This study explored the algae, zooplankton, macroinvertebrate, fish, and parasitic single-celled organism communities in Larus crassirostris (black-tailed gull) fecal samples from Baengnyeongdo, Hongdo, and Ulleungdo in South Korea. The fecal samples can identify key species consumed by black-tailed gull, providing insights into their, trophic interactions, and habitat dependencies. Using DNA metabarcoding, we identified algae, zooplankton, macroinvertebrate, fish, and intestinal and single-celled parasite species in the fecal samples. Parasitic single-celled organisms, such as Rhogostoma sp., Rhogostoma schuessleri, Eimeria furonis, and Aggregata eberthi, showed differing relative abundances at each sampling location, indicating variability in parasite diversity in the fecal DNA analysis of birds at each site. Intestinal parasites showed similar site-specific variability, though Clistobothrium sp. and Tetrabothrius sp. were common at all locations. Algae species, including Heterocapsa steinii, Heterocapsa niei, and Sargassum cristaefolium, also displayed habitat-specific patterns, as did zooplankton, with Calanus sp., Corycaeus speciosus, and Caprella californica being dominant on Baengnyeongdo, Hongdo, and Ulleungdo, respectively. In the macroinvertebrate communities, Octopus sinensis was prevalent at all locations but at varying abundances. Site-specific dominant fish species were also identified, with Ammodytes personatus, Decapterus maruadsi, and Arctoscopus japonicus highly predominant on Baengnyeongdo, Hongdo, and Ulleungdo, respectively. Other fish species, such as Ammodytes hexapterus, were detected in lower frequencies, suggesting a diverse diet for the seabirds. These results offer insights into the species composition and ecological dynamics in black-tailed gull populations across disparate Korean islands.

Unravelling urban nesting site selection in an opportunistic gull: an integrated analysis of micro-spatial habitat and litter quantification

The proliferation of gull populations in urban areas has led to an increase in human-gull conflicts, especially in highly populated cities where these opportunistic predators are often considered a nuisance. There is a lack of data regarding the selection of nesting sites by gulls, so management measures at nesting level cannot be implemented. Here, we investigated the main environmental factors that explain the nesting preferences of the yellow-legged gull (Larus michahellis) in urban areas, using the population in the city of Barcelona (NE Spain) as study model. We conducted an integrated analysis that combines micro-scale habitat selection assessments of 148 urban nesting sites with a macro-scale assessment of gull movements derived from GPS tracking of breeding yellow-legged gulls. We also analysed the type and abundance of litter in nests and main factors related to this. Nests were mainly found on flat roofs or above a structure on the main roof located at corner placements and situated on gravel substrate. Nest selection showed a negative relation to port distance and a building height beyond 12 m. The presence of litter was detected in more than 80% nests and was related to population density. Understanding the ecology of yellow-legged gulls in urban areas has implications for urban population management to prevent nest establishment.

Interspecies conflict, precarious reasoning, and the gull problem in the Gulf of Maine.

Contemporary conservation science requires mediating conflicts among nonhuman species, but the grounds for favoring one species over another can be unclear. We examined the premises through which wildlife managers picked sides in an interspecies conflict: seabird conservation in the Gulf of Maine (GOM). Managers in the GOM follow a simple narrative dubbed the gull problem. This narrative assumes Larus gulls are overpopulated and unnatural in the region. In turn, these assumptions make gulls an easy target for culling and lethal control when the birds come into conflict with other seabirds, particularly Sterna terns. Surveying historical, natural historical, and ecological evidence, we found no scientific support for the claim that Larus gulls are overpopulated in the GOM. Claims of overpopulation originated from a historical context in which rising gull populations became a nuisance to humans. Further, we found only limited evidence that anthropogenic subsidies make gulls unnatural in the region, especially when compared with anthropogenic subsidies provided for other seabirds. The risks and consequences of leveraging precarious assumptions include cascading plans to cull additional gull populations, obfuscation of more fundamental environmental threats to seabirds, and the looming paradox of gull conservation-even if one is still inclined to protect terns in the GOM. Our close look at the regional history of a conservation practice thus revealed the importance of not only conservation decisions, but also conservation decision-making.

Habitat suitability assessment for Saunders's Gull (Saundersilarus saundersi) in the Yellow River Delta, China

The Yellow River Delta (YRD) is a key breeding place for Saunders's Gull (Saundersilarus saundersi), one of the vulnerable birds in the world. Thus, a thorough understanding of the key environmental factors influencing its suitable habitat holds great value for its conservation. Previous researches focused on Saunders's Gull's population changes and habitat features of breeding places in the nature reserve. However, its habitat suitability in the whole YRD has not been studied systematically, hindering the formulation of macro-protection policies to a certain extent. On the basis of occurrence records and environmental variables, we constructed an optimized MaxEnt model using the ‘kuenm’ R package to investigate the potential distribution of suitable habitat for the Saunders's Gull in the YRD. Results showed that the ideal hyperparameters for the MaxEnt model were a feature combination of linear and quadratic terms, and the regularization multiplier of 0.6 after optimization, indicated a high level of prediction accuracy. The environmental factors that had a significant effect on the Saunders's Gull's distribution were land use and land cover, percentage of beach saline–alkali land (PLAND_55) and distance to coastline (D_coastline). The highly suitable habitat had an area of 258.56 km2, of which 66.63% was located within the YRD National Nature Reserve. The management of constructed wetlands should be combined with the protection of natural wetlands to avoid the disadvantage of ‘isolated island-type’ protection. The study provides insights into the quantitative relationship between waterfowl and their habitat, providing support for the sustainable development of the YRD, with certain practical significance.

Model projections reveal a recent decrease in a yellow-legged gull population after landfill closure

Model projections reveal a recent decrease in a yellow-legged gull population after landfill closure

Multi-strategy Improved Seagull Optimization Algorithm

Aiming at the shortcomings of seagull optimization algorithm in the process of searching for optimization, such as slow convergence speed, low precision, easy falling into local optimal, and performance dependent on the selection of parameters, this paper proposes an improved gull optimization algorithm based on multi-strategy fusion based on the analysis of gull population characteristics. Firstly, L–C cascade chaotic mapping is used to initialize the population so that seagulls are more evenly distributed in the initial solution space. Secondly, to improve the algorithm’s global exploration ability in the early stage, the nonlinear convergence factor is incorporated to adjust the position of seagulls in the migration stage. At the same time, the group learning strategy was introduced after the population position update to improve the population quality and optimization accuracy further. Finally, in the late stage of the algorithm, the golden sine strategy of the Levy flight guidance mechanism is used to update the population position to improve the population’s diversity and enhance the local development ability of the algorithm in the late stage. To verify the optimization performance of the improved algorithm, CEC2017 and CEC2022 test suites are selected for simulation experiments, and box graphs are drawn. The test results show that the proposed algorithm has apparent convergence speed, accuracy, and stability advantages. The engineering case results demonstrate the proposed algorithm’s advantages in solving complex problems with unknown search spaces.

Comparative analysis of the gut bacteria of the relict gull (Larus Relictus) and black-necked grebe (Podiceps Nigricollis) in Erdos Relic Gull National Nature Reserve in Inner Mongolia, China.

The gut microbiota promotes host health by maintaining homeostasis and enhancing digestive efficiency. The gut microflora in wild birds affects host physiological characteristics, nutritional status, and stress response. The relict gull (Larus Relictus, a Chinese national first-class protected species) and the black-necked grebe (Podiceps Nigricollis, a secondary protected species) bred in the Ordos Relic Gull National Nature Reserve share similar feeding habits and living environments but are distantly related genetically. To explore the composition and differences in the gut microbiota of these two key protected avian species in Erdos Relic Gull National Nature Reserve and provide a basis for their protection, 16S rRNA gene high-throughput sequencing was performed and the gut microbial diversity and composition of the relict gull (L. Relictus) and black-necked grebe (P. Nigricollis) was characterized. In total, 445 OTUs (operational taxonomic units) were identified and classified into 15 phyla, 22 classes, 64 orders, 126 families, and 249 genera. Alpha diversity analysis indicates that the gut microbial richness of the relict gull is significantly lower than that of the black-necked grebe. Gut microbe composition differs significantly between the two species. The most abundant bacterial phyla in these samples were Proteobacteria, Firmicutes, Fusobacteria, and Bacteroidetes. The prominent phylum in the relict gull was Proteobacteria, whereas the prominent phylum in the black-necked grebe was Firmicutes. The average relative abundance of the 17 genera identified was greater than 1%. The dominant genus in the relict gull was Escherichia-Shigella, whereas Halomonas was dominant in the black-necked grebe. Microbial functional analyses indicate that environmental factors exert a greater impact on relict gulls than on black-necked grebes. Compared with the relict gull, the black-necked grebe was able to use food more efficiently to accumulate its nutrient requirements, and the gut of the relict gull harbored more pathogenic bacteria, which may be one reason for the decline in the relict gull population, rendering it an endangered species. This analysis of the gut microbial composition of these two wild avian species in the same breeding grounds is of great significance, offers important guidance for the protection of these two birds, especially relict gulls, and provides a basis for understanding the propagation of related diseases.

Evaluating the dependence of opportunistic Yellow‐legged Gulls (Larus michahellis) on marine habitat and fishing discards

Several bird species benefit from anthropogenic food subsidies, such as landfills and fishing discards, that are being reduced owing to introduced legislation. For instance, since 2019, Europe has passed legislation to reduce dramatically the amount of fisheries discards through the Landing Obligation (LO), which states that all fish species under Total Allowable Catch (TAC) should not be discarded at sea. This European discard ban is expected to impact some gulls, as several gull populations have been observed to be heavily reliant on this resource. In this work, GPS tracking data from adult Yellow‐legged Gulls Larus michahellis and Vessel Monitoring System (VMS) data (i.e. detailed data of the spatial distribution of fishing vessels) are used to determine the utilization of the marine habitat and the level of interaction of gulls with fishing activity offshore and discards in the south‐eastern part of the Bay of Biscay. We found that these gulls had a low use of the marine habitat (ca. 15%) compared with terrestrial habitats, in contrast to the ca. 40% of the diet of this population which comprises marine prey. Furthermore, we detected that most of the gull tracking positions at sea did not interact with the fishing vessels (an overlap of 21.5% between gulls and VMS data). Conversely, other gull populations of the Iberian Peninsula were found to depend much more strongly on fishing activity. Therefore, the Yellow‐legged Gull population of the SE Bay of Biscay did not obtain most of its fish prey from interactions with offshore fishing activity but most possibly by taking fish remains in harbours and by feeding themselves. Consequently, we expect a minimal effect of the European policies oriented to ban fishing discards offshore on this population, which would be more affected by policies directed towards the reduction of food availability in landfills or fish landing management in harbours.

The Impact of Breeding Yellow-Legged Gulls on Vegetation Cover and Plant Composition of Grey Dune Habitats

The establishment of large populations of yellow-legged gull Larus michahellis in coastal and urban areas can lead to strong changes in vegetation cover and composition through creating physical disturbance in the vegetation and impacting the soil quality through defecation. In this study, we evaluated the effects of breeding yellow-legged gull populations on tall and short vegetation cover and plant species composition in old (occupied for 13 years) and new (occupied for 3 years) colony sites in grey dunes of the Algarve, southern Portugal. In each site, sampling plots were used to measure the percentage of vegetation cover in areas with and without breeding gulls. In the old colony site, the cover by tall vegetation was substantially reduced and the cover by short vegetation substantially increased in the areas where gulls are breeding in comparison with the adjacent areas. In the new colony sites, there were only minor differences. The increase in cover of short vegetation in the breeding area of the old colony site was mostly by nitrophilous species (Paronychia argentea and Malcolmia littorea) and should be explained by the decrease in vegetation cover of tall plant species and by feces deposition. Tall and slow-growing species Suaeda maritima and Helichrysum italicum covers were negatively affected. Our results showed that yellow-legged gulls affected vegetation cover and composition of grey dunes after 3 years of consecutive breeding, and this should be considered in the management of these habitats where breeding yellow-legged gulls are increasing.

Changes in the feeding ecology of an opportunistic predator inhabiting urban environments in response to COVID-19 lockdown.

Urban-dwelling species present feeding and behavioural innovation that enable them to adjust to anthropogenic food subsidies available in cities. In 2020, the SARS-CoV-2 virus outbreak resulted in unprecedented reduction in the human activity worldwide associated with the human lockdown. This situation opened an excellent opportunity to investigate the capability of urban wildlife to cope with this anthropopause event. Here, we investigated the effects of the COVID-19 lockdown on the feeding strategies of the urban yellow-legged gull (Larus michahellis) population inhabiting the highly dense city of Barcelona (NE Spain). We compared the diet of chicks (through stomach content and stable isotope analyses) sampled randomly around the city of Barcelona before (2018 and 2019), during (2020) and after (2021) the COVID-19 lockdown. The results revealed that the anthropopause associated with the lockdown had an effect on the diet of this urban-dwelling predator. The diversity of prey consumed during the lockdown was lower, and consumption of urban birds (pigeons and parakeets) and marine prey (fishery discards and natural prey) decreased during the year of lockdown. Although it was not analysed, these diet changes probably were associated with variations in the availability of these resources due to the decrease in human activity during the lockdown. These results demonstrate the trophic flexibility of urban-dwelling species to cope with the changes in the availability of human-related anthropogenic resources in urban marine ecosystems.

Yellow-legged gull populations (Larus michahellis) link the history of landfills to soil eutrophication and time-related vegetation changes on small Mediterranean islands

Seabird colonies have a strong influence on both the physical and chemical soil parameters and plant communities of the islands where they settle to nest. Scientists have studied the effects of the demographic explosion of seabird populations, but few have explored the long-term effects when the colonies were in decline. The aim of this study was to investigate diachronic changes over a 24 year period of soil parameters, floristic composition and plant functionnal types (Raunkiaer growth forms and Grime life strategies) up to the decrease of the number of nesting yellow-legged gulls (Larus michahellis Naumann, 1840) on Mediterranean islands. We used 78 permanent plots to survey the vegetation and the soil parameters on 9 islands and one mainland area within the Calanques National Park (south east of France), for three periods (i.e., 1997, 2008, 2021).Since 1997, the increase of nesting gulls has caused a nitrogen and pH increase and organic carbon and C/N ratio decrease, although the values were still higher than mainland plots without nesting gulls. This has led to changes in plant species composition e.g., higher values of N favouring the development of ruderal plant species, still present in high frequency in 2021. Furthermore, plant species highly tolerant to disturbances (i.e., R Grime strategy) in harsh environments were still favoured even after the decline of gull abundance. However, both the frequency of the chamaephytes and the vegetation cover has increased with the decline of gull colony. In 2021, measures of trace elements' concentrations and calculation of pollution load index (Cu, Pb and Zn) reveals relatively low multi-contamination levels on the mainland and the archipelagos.On naturally oligotrophic and semi-arid Mediterranean islands, gull colonies induce a persistent alteration in soil characteristics that still influences plant communities (composition and functional types), 11 years after the decline in bird abundance.

Interactions between breeding gulls and monofilament lines at one of the main recreational fishing sites in Argentina

Monofilament fishing lines lost or discarded during recreational fishing activities often result in negative impacts on marine organisms. We assessed the interactions between Kelp and Olrog's gulls (Larus dominicanus and L. atlanticus, respectively) and recreational fishing at Bahía San Blas, Argentina. Monofilament lines constituted 61 and 29 % of total debris items recorded along beaches in the low and high fishing seasons, respectively. A total of 61 balls of tangled lines were also found within Kelp and Olrog's gull colonies. No Olrog's Gulls but nine Kelp Gulls were found tangled with monofilament lines within colony boundaries, seven of which were caught in vegetation. No Kelp or Olrog's gulls foraging in recreational fishing areas were observed tangled with lines. Monofilament lines did not negatively affect gull populations during the study period, but actions are needed to correctly manage their disposal given the relevance of Bahía San Blas as a recreational fishing area in the region.

Active breeding seabirds prospect alternative breeding colonies

Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Prospecting in active breeders occurred in 85.7% of studied species, across 61.3% of sampled populations. Prospecting was more common in populations with frequent inter-annual changes of breeding sites and among females. These results contradict theoretical models which predict that prospecting is expected to evolve in relatively predictable and stable environments. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and understand the consequences of prospecting on fitness at the individual and population level.

Movement patterns of immature Yellow-legged Gulls Larus michahellis from Gran Canaria, Canary Islands

The Yellow-legged Gull subspecies Larus michahellis atlantis is thought to be resident in the Macaronesia islands, however, the movement patterns of the population remain largely unknown. We conducted an eight-year (2010–19) ringing and re-sighting program on the island of Gran Canaria (GC), Canary Islands, with an aim of estimating the movement patterns of its gull populations. Re-sighting data revealed that most gulls were observed within 50 km of their natal sites; the farthest locality where studied gulls were seen was Dakhla (500 km from GC) in northwestern Africa. Our findings are compatible with the Yellow-legged Gulls adopting either a GC residency with some dispersal to other islands within the Canary Islands archipelago or to northern Africa, or a true partial migration strategy. Return to GC by some of the gulls that were observed outside GC suggests that philopatry to their natal site could be high, though this should be the focus of further investigation.

New records of ectoparasites from the Black-headed Gull, Chroicocephalus ridibundus (Linnaeus, 1766) in Algeria

The Black-headed Gull, Chroicocephalus ridibundus Linnaeus, 1766, is a migratory bird that winters along the entire Algerian coast and is considered a protected species. In this study, we report the first-ever collection and identification of ectoparasites from Black-headed Gulls in the province of Boumerdes, Algeria. From October and November of 2020 and 2021, a total of 45 live Black-headed Gulls were captured using modified Bal-chatri traps and examined for the presence of ectoparasites. The results revealed a total of 3537 ectoparasite specimens, 264 of which belonged to Phthiraptera and 3273 to Acari. Within Phthiraptera, two species from the suborder Ischnocera were identified: Saemundssonia lari Fabricius, 1780, with a prevalence of 62.22%, and Quadraceps punctatus Burmeister, 1838, with a prevalence of 93.33%. Additionally, one species from the suborder Amblycera, Actornithophilus piceus lari Packard, 1870, was found with a prevalence of 86.66% and the lowest mean intensity with the value of 0.90. As for Acari, Zachvatkinia larica Mironov, 1989, was the most common with a prevalence of 71.11% and the highest mean intensity value of 102.28. Notably, all the recorded parasite species found in the Black-headed Gull in this study are reported in Algeria and in North Africa for the first time. The Pearson’s correlation test indicated a significant difference in parasite infestation of the gull population (r = 0.716; p = 0.046).

Long-term impact on the breeding birds of a semi-offshore island-based wind farm in Åland, Northern Baltic Sea

Breeding bird populations were monitored at a wind farm in the Båtskär area of the southern Åland archipelago in 2006–2017. The area is situated in the outer archipelago and comprises four islands with six wind turbines in total. The wind turbines began operating in autumn 2007. An environmental impact assessment for the area was conducted in 2002. A control area called Stenarna, located 22 km NW of Båtskär, was used for comparison. The Båtskär area annually recorded 850–1,050 pairs of breeding birds. Four species showed significantly decreasing trends in Båtskär, namely the Common Eider Somateria mollissima, Lesser Black-backed Gull Larus fuscus, Herring Gull L. argentatus , and Black Guillemot Cepphus grylle. In Stenarna, only the Common Eider significantly decreased over the same period. The Arctic Tern Sterna paradisaea increased in both areas, while the Velvet Scoter Melanitta fusca, Red-breasted Merganser Mergus serrator, Common Gull Larus canus, Rock Pipit Anthus petrosus, and White Wagtail Motacilla alba increased in Stenarna, the control area. The Herring Gull population decline is unlikely to be related to the wind farm. However, the proximity of a wind turbine to a breeding colony of the Lesser Black-backed Gull has most likely contributed to its decline. The reason for the Black Guillemot decline in Båtskär is unknown. The decline of Common Eider in both areas may be connected to increasing predation from White-tailed Eagles Haliaeetus albicilla. Some species, such as the House Martin Delichon urbicum and auks, have benefitted from the wind farm construction. They can utilize new microhabitats created by the construction, while other species, such as the Common Eider, gain protection against predation because of human activities.

Health status indices of Kelp Gull populations in South Africa

ABSTRACT Kelp Gulls Larus dominicanus are widespread globally due to their ability to exploit a wide variety of resources and foraging habitats inland, in coastal areas and offshore. However, the increasing availability of anthropogenic diet items might potentially impact the health of their populations. We investigated body condition and parasite loads of incubating adult Kelp Gulls and their chicks at seven South African breeding colonies with varying proximity to landfills. Adult body condition indices did not differ significantly among colonies during the incubation period but were on average highest at one of the urban colonies, Strandfontein, which is next to a large landfill site in Cape Town. The only blood parasite identified was Haemoproteus spp. Prevalence overall was low, but significantly higher in adults than in chicks. Yeast cells (Candida spp.) were identified in faecal smears and coincided with higher body condition index values in incubating adults. Our results suggest that urban landscapes currently have little impact on these aspects of gull health, at least on individuals in good enough condition to breed.

The influence of nest location and the effect of predator removal on Cape Gannet Morus capensis egg predation by Kelp Gulls Larus dominicanus vetula

The breeding range of the Cape Gannet Morus capensis currently extends to six of the ten islands formerly utilised by this species. The Cape Gannet is classified as an endangered species with a rapidly declining population. Since the mid-1950s, the global population has declined by 51% due to multiple causes, including egg predation by the Kelp Gull Larus dominicanus vetula. To assess the effect of this predation, we monitored 100 nests over an 11-week period in 2018 at the Lambert’s Bay colony in South Africa. To assess the effect of selective predator removal on the likelihood of predation, data were collected from 2006 and 2018. Our objective was to assess whether nest location and predator removal affected the likelihood of egg predation. The peripheral nests saw a higher level of egg loss (average 1.5 eggs per week) compared with the central nests (average 1 egg per week). Predator control of Kelp Gulls was implemented in 2015, 2017 and 2018. Between years, selective culling decreased the number of Cape Gannet eggs predated. However, within years, except for 2015, the predation rate on Cape Gannet eggs increased post-culling during the same year of implementation. In all three of the implementation years, predation started again (within 48 hours) after the culling commenced. Predation by this indigenous gull species is natural; however, certain human activities might have supported larger populations of Kelp Gulls leading to elevated predation intensity. The most notable being the ever-increasing existence of dumpsites and other sources of food. Predation is affecting the Cape Gannet breeding population; therefore, we suggest that an alternative, long-term, and sustainable solution be planned and implemented to reduce the effects thereof.