Lars H. Holbech, Francis Gbogbo, Timothy Khan Aikins. 2018: Abundance and prey capture success of Common Terns (Sterna hirundo) and Pied Kingfishers (Ceryle rudis) in relation to water clarity in south-east coastal Ghana. Avian Research, 9(1): 25. DOI: 10.1186/s40657-018-0116-7
Citation:
Lars H. Holbech, Francis Gbogbo, Timothy Khan Aikins. 2018: Abundance and prey capture success of Common Terns (Sterna hirundo) and Pied Kingfishers (Ceryle rudis) in relation to water clarity in south-east coastal Ghana. Avian Research, 9(1): 25. DOI: 10.1186/s40657-018-0116-7
Lars H. Holbech, Francis Gbogbo, Timothy Khan Aikins. 2018: Abundance and prey capture success of Common Terns (Sterna hirundo) and Pied Kingfishers (Ceryle rudis) in relation to water clarity in south-east coastal Ghana. Avian Research, 9(1): 25. DOI: 10.1186/s40657-018-0116-7
Citation:
Lars H. Holbech, Francis Gbogbo, Timothy Khan Aikins. 2018: Abundance and prey capture success of Common Terns (Sterna hirundo) and Pied Kingfishers (Ceryle rudis) in relation to water clarity in south-east coastal Ghana. Avian Research, 9(1): 25. DOI: 10.1186/s40657-018-0116-7
Abundance and prey capture success of Common Terns (Sterna hirundo) and Pied Kingfishers (Ceryle rudis) in relation to water clarity in south-east coastal Ghana
Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. We studied the relationship between water clarity and the abundance and prey capture success of Pied Kingfishers (Ceryle rudis) and Common Terns (Sterna hirundo) in two polluted coastal waters of south-east Ghana—the Weija Lake and Densu Delta Ramsar Site.
Methods
On each wetland, data on abundance and prey capture success of plunge-divers were collected in four spatio-temporal quadrats of 100 m?×?100 m and analysed with concurrent measurements of water quality parameters using GLM regression with Pearson's correlation coefficients.
Results
Mean prey capture success of Pied Kingfishers (34.7?±?13.1%) and Common Terns (35.3?±?11.0%) were similar but the two species responded differently to water clarity. The abundance of Common Terns was significantly higher in less transparent/more turbid water while that of Pied Kingfishers showed no significant relationship with turbidity and transparency. In contrast, the prey capture success of Common Terns was neither related to transparency nor turbidity, as opposed to that of Pied Kingfishers which was significantly higher in more turbid/less transparent waters. Correlations between capture success and bird abundance, as well as capture attempts were insignificant, suggesting that increased fish abundance associated with cloudy water may not necessarily promote higher abundance and capture success of foraging birds. Thus, when foraging in less transparent water, capture success may depend more on predator avoidance by fish prey than lower prey detectability of foraging birds.
Conclusion
Within a gradient of 15-51 cm transparency studied, lower water clarity did not constrain prey capture success of Common Terns and Pied Kingfishers. Further studies on the foraging ecology of plunge-divers in coastal Ghana are however required to make firm conclusions on the relationship between water clarity and foraging birds and fish prey abundances, as well as capture success.
The Golden Pheasant (Chrysolophus pictus), a species endemic to China, is found in 12 provinces of central China (Lei and Lu, 2006). This distinctive species has received much attention lately, primarily due to the rapid decline of its numbers during the 20th century. Because of its colorful plumage, rampant hunting has been recognized as one of the important factors leading to a population decline of this species in China (Zheng and Wang, 1998).
For this species, concern about conservation has been well documented in China (Lu et al., 1992; Jiang et al., 1996; Yu et al., 1997; Shao, 1997, 1998; Zhang et al., 2001, 2002; Li and Zhang, 2006). Research of its digestive system was carried out on stomach vas (Zhang and Yu, 2000a), microstructure of digestive tract and liver (Zhang et al., 2000; Zhang and Yu, 2000b; Zhang et al., 2002) and immunohistochemistry of endocrine cells in the digestive tract (Li and An, 2009). However, little information has been published about the diet of the Golden Pheasant (Yao, 1991; He et al., 1994; Yu and Liang, 1996; Shao, 1998), especially with respect to the anatomical structure of its digestive tract. A study on the gastrointestinal tract of the Adélie Penguin (Pygoscelis adeliae) by Olsen et al. (2002) indicated that the digestive system has anatomical and functional adaptations typical for carnivorous birds. In birds that do have a crop, its size and shape differ between species according to feeding habits and digestive strategies. One extreme example is the leaf-eating Hoatzin (Opisthocomus hoazin), in which the crop has replaced the proventriculus and the gizzard as the primary site of digestion, allowing microbial foregut fermentation of dietary structural carbohydrates (Grajal et al., 1989). The gizzard of this bird develops from the posterior part of the stomach called the ventriculus. Pebbles that have been swallowed are often retained in the gizzard of grain-eating birds and facilitate the grinding process (Miller et al., 2002).
Here, we present a study on the diet in winter and a morphological description of the gastrointestinal tract of the Golden Pheasant. We also consider the implications of our results for the conservation of the species in China.
Methods
Sixty-two pheasants, fifty-two males and ten females, were confiscated from poachers by the Shaanxi Nature Reserve and Wildlife Administration Station during the 2002/2003 winter season. Thirty-seven birds were collected at Shuangmiaozi, Zhouzhi County (108°14′–108°18′E, 33°45′–33°50′N) and the others at Yingge, Taibai County (107°38′–107°40′E, 34°03′–34°05′N), Shaanxi Province in the Qinling Mountains. Necropsy of these birds confirmed that they were all captured by trapping. Because most birds were relatively fresh and not scavenged, their entire corpses were frozen at –4℃.
Corpses were left to thaw overnight, crops and gizzards were removed and their contents were weighed on an electronic balance to ±0.1 g. Individual food items in crops were identified by species where possible, using standard taxonomic methods. Because the material contained in the gizzards was too digested to identify, it could only be used for analysis of their pebbles.
Total body mass (BM, n=62) was recorded to nearest 0.1g and standard body length (SBL, n=62) (tip of the beak to base of the tail) to 1 cm. At the distal end of the oesophagus the expanded crop is found that contains food temporarily. The proventriculus is considered part of the gastric region, shaped like a funnel situated between the crop and the gizzard. The muscular gizzard is defined as part of the gastric region between the proventriculus and the pyloric sphincter. The contents of each of the principal sections of the digestive tract i.e., the oesophagus (n=15), crop (n=62), proventriculus (n=15), gizzard (n=37), small intestine (n=15), cecum (n=15) and colon (n=15), were weighed to 0.1g with an electronic balance. The wet tissue weight of each part, as well as the liver, was weighed to within 0.1g. The length of the oesophagus, proventriculus and intestine was measured to within 1mm with each segment fully extended, but not stretched. Both length and width of the gizzard were measured to 1 mm. The pH of the contents and the mucosa of the different sections of the digestive system for only five individuals (n=5) were measured with a digital pH electrode (PHS-25B, Shanghai, China) and special indicator pH paper.
Variations in the content of crops of individual birds were statistically analyzed using One Sample T test assuming equal variances. Pearson correlation analyses (two-tailed) were used to determine the significance between: 1) the wet weight of the gizzard and body mass; 2) dry weight of the pebbles and weight of digesta in the gizzard. A probability of < 0.05 was considered statistically significant. All values were reported as means ± SD.
Results
Only three out of 62 crops were empty. The mass of the contents ranged from 0 to 91.8 g with an average of 24.9±20.4 g (n=62) and varied markedly significant among individuals (t=8.80, df=61, p=0.000). The Golden Pheasant eats exclusively vegetarian items in the winter, with at least 14 species of vegetables, including crops and other plant species (Table 1). Wheat leaves, maize seeds and Chinese gooseberry accounted for 61.2% of the items and almost four-fifth of the biomass consumed. Other items were too infrequent to be important.
Table
1.
Frequency of food items and percentage of biomass by taxa in crops of the Golden Pheasants in winter
Mean standard body length was 32.6±4.7 cm (n=62) while the mean total body mass was 738.6±75.7 g (n=62). The digestive tract of the Golden Pheasant is composed of an oesophagus, a stomach and a relatively long intestine. There is an ellipsoidal crop, which holds food temporarily, at the distal end of the oesophagus. The stomach consists of two closely adjacent compartments: an infundibular proventriculus and a deep purple-red muscular gizzard, shaped like a flattened sphere. The intestine consisted of a very long small intestine, two fully-developed caeca and a short colon. The wet tissue weight of the total gastrointestinal tract represented 10.04±1.07% (n=15) of BM.
The wet tissue weight of the oesophagus (Table 2) ranged from 1.5 to 2.5g and contributed 0.30±0.06% (n=15) to BM. It is relatively short, ranging from 81 to 107 mm, i.e., 0.29±0.04× SBL (n=15). The surface pH of the mucosa of the oesophagus was slightly acidic, with a drop in acidity from the proximal to the distal part (Table 3). The birds have a crop (expandable pouch) at the end of the oesophagus, where its many food items were easily identified. The crop measured 57.8±10.4mm in length (n=62). The tissue wet weight averaged at 5.3±1.4 g and contributed 0.79±0.19% to BM (n=62). The mean surface pH of the mucosa of the crop was 3.8±1.0 (n=5).
Table
2.
Contents, tissue wet weights and size [means ± SD (n)] of different parts of digestive tract in the Golden Pheasant (gender combined)
The proventriculus shaped like a funnel contained 0.91±1.1 g (n=15) digestive mucus. It ranged from 71 to 82 mm, with an average of 74.5±4.3 mm in length and its wet tissue weight contributed 0.59± 0.16% (n=15) to BM. The contents of the proventriculus were acidic (average pH 4.7±0.7, n=5).
The gizzard is located between the proventriculus and the duodendum and contains much digestive material which was more difficult to identify than that in the crop, with the wet weight of its contents as much as 16.5±4.3 g (n=37). The deep purple-red gizzard was 60.0±4.4 × 49.2±5.5 mm (n=37) in size. This tissue, with an average wet weight of 35.9±4.7 g (n=37), contributed 4.6±0.5% (n=37) to BM, was the largest part of the digestive tract. The wet tissue weight was positively correlated with the BM (Pearson r=0.566, p < 0.01, n=37). Pebbles of different sizes (0.5–3 mm in diameter) were very frequent in this section of the stomach. The average dry weight of the pebbles was 10.4±2.5 g and positively correlated with the weight of digesta in gizzard (Pearson r=0.747, p < 0.01, n=37). The mean number of pebbles was 652.3±137.7, ranging from 400 to 1000 (n=37). The mean surface pH of the mucosa of the gizzard ranged from 3.5 to 4.1 (Table 3).
The small intestine comprised a duodenum and an ileojejunum, measuring 3.4±0.5×SBL (n=15). It contained, on average, 12.9±6.5 g (n=15) of digesta (Table 1). The wet tissue weight of the small intestine contributed 1.75±0.37% (n=15) to BM. The mucosa surface pH of the small intestine at the distal end ranged from 5.1 to5.5, which was higher than that of the gizzard (Table 3). The average of the fully developed paired caecum was 203.5±25.2 mm long for the left and 215.5±23.2 mm for the right (n=15), measuring 0.60±0.11 and 0.64±0.11×SBL (n=15) respectively. The length of the right caecum was longer than that of the left, but this difference was not significant (t=1.357, p=0.1857, n=15). The colon was relatively short (103.3±10.2 mm, n=15), contributing only 0.36±0.09% (n=15) to BM. The surface pH of the caeca and the colon was slightly acidic (Table 3).
Discussion
This study provides information on the wintering diet of the Golden Pheasants in the Qinling Mountains, as assessed by an analysis of the crop contents. Crop contents of the breeding Golden Pheasant sampled ten years ago in the Qinling Mountains contains almost all vegetable items, such as fruits and seeds (59%), lower plants, twigs and leaves (27%) and a few insects (14%) (Yao, 1991). There were also regional variations in the diets. Wintering Golden Pheasant on the south slopes of the Qinling Mountains fed mainly on bamboo leaves and mosses (80%) (He et al., 1994), but the pheasant consumed largely fruits of Pyracantha fortuneana in Mt. Xianrenshan in Guizhou Province during the winter (Shao, 1997). The Golden Pheasant is mostly found in coniferous-deciduous evergreen mixed forests and fall-leaf mixed forests. Our data presented here indicated that the wintering Golden Pheasant lived near human settlements in flocks on the edge of forests and relied primarily on seeds and leaves of crops and it is likely that they are easily captured by traps or poisoning baits during this period. An extra investigation indicated that a large number of Golden Pheasants were poached by local farmers, especially on snowy days. So the managers of the nature reserves should focus their energy on the bird in the areas near human settlements in the winter. Due to its colorful plumage, illegal over-hunting is still the main threat to the species. For example, the number of skins purchased by animal-products companies in areas of western Hunan Province has reached 6000–8000 since the 1960's (Zheng and Wang, 1998).
The digestive system of the Golden Pheasant also has anatomical and functional adaptations, typical for herbivorous birds. The bird has a crop (expandable pouch) in the end of the oesophagus, which differs both from the carnivorous Adélie Penguin (Olsen et al., 2002) and the extreme leaf-eating Hoatzin (Grajal et al., 1989). The gizzard of the Golden Pheasant is characterized by a massive muscular wall and has a lining that appears to be keratinous. The gizzard grit of the Golden Pheasant observed occurred often, as also seen in seabirds (Cowan, 1983; Olsen et al., 2002) and grain-eating birds (Miller et al., 2002). The markedly significant correlation between the dry weight of pebbles and the weight of digesta in the gizzard indicates specialization of the herbivorous diets. Studies of the Japanese Quails (Coturnix coturnix) have shown that the gizzard could double in size in response to an increased proportion of fiber in the diet (Starck, 1999). The wet tissue weight of the gizzard accounted for 4.6% of body mass in the Golden Pheasant, compared with 1.8% in the Temminck's Tragopan (Tragopan temminckii), 2.0% in the Blood Pheasant (Ithaginis cruentus) (Hou, in litt.), found in regions with relatively higher elevations, which relies mainly on ferns (Shi et al., 1996; Jia and Sun, 2008). The wet weight of this tissue is much lower in several carnivorous penguin species (Olsen et al., 19972002; Jackson, 1992).
The relative length of the small intestine is generally shorter in carnivorous birds, such as the Procellariidae (1.4–2.8×SBL) (Olsen et al., 2002) than that of herbivorous species, including that of the Golden Pheasant (3.4×SBL). The mean retention time of digesta in seabirds is significantly correlated with intestinal length (Jackson, 1992), indicating a relatively long intestinal passage time in the Golden Pheasant.
Hanssen (1979) compared the microbial conditions in the caeca of wild and captive willow ptarmigan. The function of the caecum may vary, but symbiotic microbial fermentation to some degree is expected to occur in most birds. Wild herbivorous birds such as ptarmigans and grouse (weight 400–1400g) have large paired caeca with a combined length of 70–150mm (Pulliainen, 1976) and are much longer (about 420 mm) in the Golden Pheasant as mentioned above, predicated on high concentrations of plant cell-wall carbohydrates (Hanssen, 1979).
Acknowledgements
We are very grateful to the Shaanxi Nature Reserve and Wildlife Administration Station for providing the Golden Pheasants and to Mrs. Wang J., Wang X.W., Li Q. and Hou Y.B. for carrying out bird measurements. Special thanks are given to Mr. Hou Y.B. for providing his unpublished diet information of the other Galliformes species.
Abrahams M, Kattenfeld M. The role of turbidity as a constraint on predator-prey interactions in aquatic environments. Behav Ecol Soc. 1997;40:169-74.
Ahulu AM, Nunoo FKE, Owusu EH. Food preferences of the common tern, Sterna hirundo (Linnaeus, 1758) at the Densu floodplains, Accra. West Afr J Appl Ecol. 2006;9:1-7.
Anderson JT, Zadnik AK, Wood PB, Bledsoe K. Evaluation of habitat quality for selected wildlife species associated with island back channels. Open J Ecol. 2013;3:301-10.
Ansa-Asare OD, Asante KA. A comparative study of the nutrient status of two reservoirs in southeast Ghana. Lakes Reserv Res Manag. 1998;3:205-17.
Ansa-Asare OD, Asante KA. Changes in the chemistry of the Weija Dam Reservoir in Ghana, twenty years after impoundment. West Afr J Appl Ecol. 2005;8:35-47.
Asante KA, Quarcoopome T, Amevenku FYK. Water quality of the Weija reservoir after 28 years of impoundment. West Afr J Appl Ecol. 2008;13:125-31.
Baptist MJ, Leopold MF. Prey capture success of Sandwich Terns Sterna sandvicensis varies non-linearly with water transparency. Ibis. 2010;152:815-25.
BirdLife Int. Important Bird Areas factsheet: Densu Delta Ramsar Site and vicinity. 2018. Downloaded from on Accessed 07 Mar 2018.
Bonnington C, Weaver D, Fanning E. The habitat preference of four kingfisher species along a branch of the Kilombero River, southern Tanzania. Afr J Ecol. 2008;46:424-7.
Borah J. Occupancy pattern and food-niche partitioning among sympatric kingfishers in Bhitarkanika mangroves, Orissa. MSc Thesis. 2011; Saurashtra Univ. Rajkot, India.
Braby J, Underhill LG, Simmons RE. Prey capture success and chick diet of Damara terns Sterna balaenarum in Namibia. Afr J Mar Sci. 2011;33:225-47.
Brenninkmeijer AE, Stienen WM, Klaassen M, Kersten M. Foraging ecology of wintering terns in Guinea-Bissau. Ibis. 2002;144:602-13.
Briggs KT, Ainley DG, Spear LB, Adams PB, Smith SE. Distribution and diet of Cassin's Auklet and Common Murre in relation to central California upwellings. Proc Int Ornithol Congr. 1988;19:983-90.
Buckley FG, Buckley PA. Comparative feeding ecology of wintering adult and juvenile Royal Terns (Aves: Laridae, Sterninae). Ecology. 1974;55:1053-63.
Cramp S, Douthwaite R, Reyer H, Westerturp K. Pied Kingfisher Ceryle rudis (Linnaeus). In: Fry H, Keith S, Urban E, editors. The Birds of Africa, vol. 3. San Diego: Academic Press; 1988. p. 299-302.
Cyrus DP. The influence of turbidity on the foraging behaviour of Little Terns Sterna albifrons off the St. Lucia Mouth, Zululand, South Africa. Mar Ornithol. 1991;19:103-8.
Davoren GK, Montevecchi WA, Anderson JT. Distributional patterns of a marine bird and its prey: habitat selection based on prey and on specific behaviour. Mar Ecol Prog Ser. 2003;256:229-42.
Douthwaite RJ. Fishing techniques and foods of the pied kingfisher on Lake Victoria in Uganda. Ostrich. 1976;47:153-60.
Douthwaite RJ. Changes in Pied Kingfisher (Ceryle rudis) feeding related to endosulfan pollution from tsetse fly control operations in the Okavango Delta, Botswana. J Appl Ecol. 1982;19:133-41.
Dowsett-Lemaire F, Dowsett RJ. The birds of Ghana. Jupille-Liege: Tauraco Press; 2014. p. 713.
Dunn EK. Studies on terns, with particular reference to feeding ecology. Ph.D Thesis. South Africa: Durham University. 1972a.
Dunn EK. Effect of age on the fishing ability of sandwich terns Sterna sandvicensis. Ibis. 1972;114:360-6.
Elliot A. Family Pelecanidae (Pelicans). In: Handbook of Birds of the World. vol 1. Barcelona: Lynx Editions. 1992.
Enstipp MR, Grémillet D, Jones DR. Investigating the functional link between prey abundance and seabird predatory performance. Mar Ecol Prog Ser. 2007;331:267-79.
Eriksson MOG. Prey detectability for fish-eating birds in relation to fish density and water transparency. Ornis Scand. 1985;16:1-7.
Flemming SP, Smith PC. Environmental influences on Osprey foraging in northeastern Nova Scotia. J Raptor Res. 1990;24:64-7.
Forsell DJ. Predatory efficiency and energetics of Belted kingfishers wintering along the Mad River. MSc Thesis. Humboldt: Humboldt State University. 1983.
Gbogbo F. The importance of unmanaged coastal wetlands to waterbirds at coastal Ghana. Afr J Ecol. 2007;45:599-606.
Gbogbo F, Attuquayefio DK. Issues arising from changes in waterbird population estimates in coastal Ghana. Bird Popul. 2010;10:79-87.
Gbogbo F, Oduro W, Oppong SK. Nature and pattern of lagoon fisheries resource utilisation and their implications for waterbird management in coastal Ghana. Afr J Aquat Sci. 2008;33:211-22.
Gbogbo F, Adaworomah BB, Asante E, Brown-Engmann GR. Human related bird flushes are of little consequence to wintering waterbirds in a tropical coastal wetland in Ghana. Wader Stud Group Bull. 2013;120:60-5.
Grimble R, Ellenbroek W, Willoughby N, Danso E, Ametekpor J. Study of development options for Ghana's wetlands (Vol. 1). Technical report to the Environmental Protection Agency and Natural Resource International. Chatham, Kent; 1998. p. 94.
Haney JC. Winter habitat of Common loons on the continental shelf of the Southeastern United States. Wilson Bull. 1991;102:253-63.
Haney JC, Stone AE. Seabird foraging tactics and water clarity: are plunge divers really in the clear? Mar Ecol Prog Ser. 1988;49:1-9.
Henkel LA. The distribution and abundance of marine birds in nearshore waters of Monterey Bay, California.MSc Thesis. California State University, Monterey Bay. 2003.
Henkel LA. Effect of water clarity on the distribution of marine birds in nearshore waters of Monterey Bay, California. J Field Ornithol. 2006;77:151-6.
Johnston DW. Feeding ecology of Pied kingfishers on Lake Malawi, Africa. Biotropica. 1989;21:275-7.
Junor FJR. Offshore fishing by the Pied Kingfisher Ceryle rudis at Lake Kariba. Ostrich. 1972;43:185.
Katzir G, Camhi JM. Escape response of Black Mollies (Poecilia sphenops) to predatory dives of a Pied Kingfisher (Ceryle rudis). Copeia. 1993;2:549-53.
Lamptey AM, Ofori-Danson PK. Review of the distribution of waterbirds in two tropical coastal Ramsar lagoons in Ghana, West Africa. West Afr J Appl Ecol. 2014;22:77-91.
Newbrey JL, Bozek MA, Niemuth ND. Effects of lake characteristics and human disturbance on the presence of piscivorous birds in Northern Wisconsin, USA. Waterbirds. 2005;28:478-86.
Ntiamoa-Baidu Y, Nyame SK, Nuoh AA. Trends in the use of a small coastal lagoon by waterbirds: Muni Lagoon (Ghana). Biodivers Conserv. 2000;9:527-39.
Piersma T, Ntiamoa-Baidu Y. Waterbird ecology and the management of coastal wetlands in Ghana 12. NIOZ Report 1995-1996. 1995. p. 105.
Quarcoopome T, Amevenku FYK. Fish community structure of Weija reservoir after 28 years of impoundment. J Appl Sci Technol. 2010;15:126-31.
Recher HF, Recher JA. The foraging behavior of the Reef Heron. Emu. 1972;72:85-90.
Reyer H-U, Migongo-Bake W, Schmidt L. Field studies and experiments on distribution and foraging of Pied and Malachite Kingfishers at Lake Nakuru (Kenya). J Anim Ecol. 1988;57:595-610.
Ropert-Coudert Y, Grémillet D, Ryan PG, Kato A, Naito Y, Le Maho Y. Between air and water: the plunge-dive of the cape gannet Morus capensis. Ibis. 2004;146:281-90.
Ropert-Coudert Y, Daunt F, Kato A, Ryan PG, Lewis S, Kobayashi K, Mori Y, Grémillet D, Wanless S. Underwater wingbeats extend depth and duration of plunge dives in northern gannets Morus bassanus. J Avian Biol. 2009;40:380-7.
Russell IA, Randall RM, Hanekom N. Spatial and temporal patterns of waterbird assemblages in the Wilderness Lakes Complex, South Africa. Waterbirds. 2014;37:1-18.
Safina C. Foraging habitat partitioning in Roseate and Common terns. Auk. 1990a;107:351-8.
Safina C. Bluefish mediation of foraging competition between Roseate and Common Terns. Ecology. 1990b;71:1804-9.
Safina C, Burger J. Common Tern foraging: seasonal trends in prey fish densities and competition with bluefish. Ecology. 1985;66:1457-63.
Safina C, Burger J. Ecological dynamics among prey fish, bluefish and foraging Common terns in an Atlantic coastal system. In: Burger J, editor. Seabirds and other marine vertebrates. New York: Columbia University Press; 1988. p. 95-173.
Shealer DA, Burger J. Comparative foraging success between adult and one-year-old Roseate and Sandwich terns. Colon Waterbirds. 1995;18:93-9.
Simmons RE, Braine S. Breeding, foraging, trapping and sexing of Damara terns in the Skeleton Coast Park, Namibia. Ostrich. 1994;65:264-73.
Sohel S, Lindström K. Algal turbidity reduces risk assessment ability of the Three-Spined Stickleback. Ethology. 2015;121:548-55.
Stempniewicz L, Darecki M, Trudnowska E, Błachowiak-Samołyk K, Boehnke R, Jakubas D, Keslinka-Nawrot L, Kidawa D, Sagan S, Wojczulanis-Jakubas K. Visual prey availability and distribution of foraging little auks (Alle alle) in the shelf waters of West Spitsbergen. Polar Biol. 2013;36:949-55.
Stienen EWM, Brenninkmeijer A. Voedselecologie van de grote sterns (Sterna sandvicensis): onderzoek ter ondersteuning van een populatie-dynamisch model. Wageningen: Instituut voor Bos- en Natuuronderzoek; 1994 (in Dutch).
Strod T, Izhaki I, Arad Z, Katzir G. Prey detection by great cormorant (Phalacrocorax carbo sinensis) in clear and in turbid water. J Exp Biol. 2008;211:866-72.
Taylor IR. Effect of wind on the foraging behaviour of common and sandwich terns. Ornis Scand. 1983;14:90-6.
WRC Ghana. Densu river basin—integrated water resources management plan. Technical Report. Water Resources Commission of Ghana. 2007. p. 83.
Watson MJ, Hatch JJ. Differences in foraging performance between juvenile and adult Roseate Terns at a pre-migratory staging area. Waterbirds. 1999;22:463-5.
Željko Pavlinec, Simon Piro, Angela Schmitz Ornés, et al. Influence of ocean primary production on the activity pattern of wintering Common Terns. Journal of Ornithology, 2025, 166(3): 633.
DOI:10.1007/s10336-025-02271-7
2.
Badreddine kanouni, Abdelbaset Laib, Salah Necaibia, et al. Pied kingfisher optimizer for accurate parameter extraction in proton exchange membrane fuel cell. Energy, 2025, 325: 136079.
DOI:10.1016/j.energy.2025.136079
3.
Robert J. Lennox, Marius Kambestad, Saron Berhe, et al. The role of habitat in predator–prey dynamics with applications to restoration. Restoration Ecology, 2025, 33(3)
DOI:10.1111/rec.14354
4.
Nickson Erick Otieno, Erick Shidavi. Piscivorous bird assemblages at functional rather than species level better predict predation risk on open culture fish ponds within enhanced fertilization treatment regime. Hydrobiologia, 2024, 851(16): 3963.
DOI:10.1007/s10750-024-05552-z
5.
Anas Bouaouda, Fatma A. Hashim, Yassine Sayouti, et al. Pied kingfisher optimizer: a new bio-inspired algorithm for solving numerical optimization and industrial engineering problems. Neural Computing and Applications, 2024.
DOI:10.1007/s00521-024-09879-5
6.
Ian J. Ausprey. Eye morphology contributes to the ecology and evolution of the aquatic avifauna. Journal of Animal Ecology, 2024, 93(9): 1262.
DOI:10.1111/1365-2656.14141
7.
Joanna B. Wong, Simeon Lisovski, Ray T. Alisauskas, et al. Variation in migration behaviors used by Arctic Terns (Sterna paradisaea) breeding across a wide latitudinal gradient. Polar Biology, 2022, 45(5): 909.
DOI:10.1007/s00300-022-03043-2
8.
Simon Piro, Angela Schmitz Ornés. Revealing different migration strategies in a Baltic Common Tern (Sterna hirundo) population with light-level geolocators. Journal of Ornithology, 2022, 163(3): 803.
DOI:10.1007/s10336-022-01986-1
9.
Johan Diepstraten, Jacob Willie. Assessing the structure and drivers of biological sounds along a disturbance gradient. Global Ecology and Conservation, 2021, 31: e01819.
DOI:10.1016/j.gecco.2021.e01819
10.
Lars Haubye Holbech, Cara Caroline Cobbinah. Pollution or Protection - What Early Survey Data Shows on Rapid Waterbird Utilisation of a Newly Established Sewage Treatment Plant in Urban Ghana, West Africa. Wetlands, 2021, 41(8)
DOI:10.1007/s13157-021-01510-w
11.
Davorin Tome, Miloš Martinović, Jelena Kralj, et al. Area use and important areas for Common Tern Sterna hirundo inland populations breeding in Slovenia and Croatia. Acrocephalus, 2019, 40(180-181): 55.
DOI:10.1515/acro-2019-0003
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