Creagrus Furcatus Research Articles

Prevalence of Toxoplasma gondii in Galapagos birds: Inference of risk factors associated with diet.

Toxoplasma gondii is a zoonotic intracellular parasite of particular concern in the conservation of wildlife due to its ability to infect all homeotherms and potentially cause acute fatal disease in naive species. In the Galapagos (Ecuador), an archipelago composed of more than a hundred islets and islands, the presence of T. gondii can be attributed to human-introduced domestic cats, but little is known about its transmission in wildlife populations. We compared the prevalence of antibodies against T. gondii in sympatric Galapagos wild bird species that differ in diet and contact with oocyst-contaminated soil to determine the relative importance of trophic habits as an exposure factor. Plasma samples were obtained from 163 land birds inhabiting Santa Cruz, one of the cat-inhabited islands, and from 187 seabirds breeding in cat-free surrounding islands (Daphne Major, North Seymour, and South Plaza). These samples were tested for the presence of T. gondii antibodies using the modified agglutination test (MAT ≥ 1:10). All seven species of land birds and 4/6 species of seabirds presented seropositive results. All great frigatebirds (Fregata minor) (N = 25) and swallow-tailed gulls (Creagrus furcatus) (N = 23) were seronegative. Prevalence ranged from 13% in Nazca boobies (Sula granti) to 100% in Galapagos mockingbirds (Mimus parvulus). It decreased from occasional carnivores (63.43%) to granivores-insectivores (26.22%), and strict piscivores (14.62%). These results indicate that the consumption of tissue cysts poses the highest risk of exposure to T. gondii for Galapagos birds, followed by the ingestion of plants and insects contaminated by oocysts as important transmission pathways.

Twelfth Report of the Washington Bird Records Committee (2016–2018)

Since its eleventh report (Merrill et al. 2019) the Washington Bird Records Committee has reviewed 219 new reports of 80 species and 9 subspecies. Of these, 163 were accepted, an acceptance rate of 74%. Seven species and two subspecies/subspecies-groups were added to the Washington state checklist: the Purple Gallinule (Porphyrio martinicus), Swallow-tailed Gull (Creagrus furcatus), Zone-tailed Hawk (Buteo albonotatus), Dusky-capped Flycatcher (Myiarchus tuberculifer), Field Sparrow (Spizella pusilla), Painted Redstart (Myioborus pictus), and Blue Grosbeak (Passerina caerulea), plus an eastern subspecies of the Song Sparrow (Melospiza melodia melodia/atlantica group) and the White-winged Dark-eyed Junco (Junco hyemalis aikeni). In addition to the regular review of reports, the committee reconsidered species on the state list supported only by sight reports. After reviewing 25 reports of 17 species, it removed six species from the state list: the Ruby-throated Hummingbird (Archilochus colubris), Little Curlew (Numenius minutus), Great Knot (Calidris tenuirostris), Whiskered Auklet (Aethia pygmaea), Red-faced Cormorant (Urile urile), and Gray-cheeked Thrush (Catharus minimus). The Washington state list now stands at 515 species.

Baseline haematology, biochemistry, blood gas values and health status of the Galapagos swallow-tailed gull (Creagrus furcatus).

The swallow-tailed gull, Creagrus furcatus, is a seabird endemic to the Galápagos archipelago. In general health, blood chemistry and haematology, parameters have not been published for this species. Blood analyses were run on samples drawn from 58 clinically healthy swallow-tailed gulls captured at Islote Pitt on San Cristóbal Island in July 2016 (28) and South Plaza Island in June 2017 (30). A point of care blood analyzer (iSTAT) was used in the field to obtain results for HCO3 -, pH, pCO2, pO2, TCO2, anion gap, chloride, creatinine, glucose, haematocrit, haemoglobin, ionized calcium, potassium, sodium and urea nitrogen. A portable Lactate Plus™ analyzer was used to measure lactate. The baseline data reported is valuable for comparisons amongst different populations in the archipelago and to detect changes in health status of Galápagos swallow-tailed gulls.

MODEL-BASED GEOMORPHOLOGY OF MALPELO ISLAND AND SPATIAL DISTRIBUTION OF BREEDING SEABIRDS

The spatial distribution of seabird nests present on Malpelo Island, the main characteristics of the islandʼs topography, and the types of substratum available for nesting were addressed using a Digital Elevation Model (DEM). The model is based on data from remote sensors (satellite images, aerial photography and panoramic photography), and from field data processed through a geographical information system. The nests of Sula granti prevail on the surfaces of Malpelo Island and neighboring islets, while those of the remaining species (S. sula, Creagrus furcatus, Anous stolidus, A. minutus and Gygis alba) are spatially restricted to the cliff margins and to crevices or caverns at different heights. The presence of terrestrial predators and predatory birds (Fregata spp.) seems to mainly explain the marginal distribution of other breeding species. The cartographic data presented here differ significantly from past and current representations, especially those concerning the islandʼs emerged surface and other geomorphologic features. This new cartographical information will support future studies on the terrestrial fauna and flora of Malpelo Island and its islets.

At-sea behavior varies with lunar phase in a nocturnal pelagic seabird, the swallow-tailed gull.

Strong and predictable environmental variability can reward flexible behaviors among animals. We used long-term records of activity data that cover several lunar cycles to investigate whether behavior at-sea of swallow-tailed gulls Creagrus furcatus, a nocturnal pelagic seabird, varied with lunar phase in the Galápagos Islands. A Bayesian hierarchical model showed that nighttime at-sea activity of 37 breeding swallow-tailed gulls was clearly associated with changes in moon phase. Proportion of nighttime spent on water was highest during darker periods of the lunar cycle, coinciding with the cycle of the diel vertical migration (DVM) that brings prey to the sea surface at night. Our data show that at-sea behavior of a tropical seabird can vary with environmental changes, including lunar phase.

Novel Haemoproteus Species (Haemosporida: Haemoproteidae) from the Swallow-Tailed Gull (Lariidae), with Remarks On the Host Range of Hippoboscid-Transmitted Avian Hemoproteids

Haemoproteus (Haemoproteus) jenniae n. sp. (Haemosporida: Haemoproteidae) is described from a Galapagos bird, the swallow-tailed gull Creagrus furcatus (Charadriiformes, Laridae), based on the morphology of its blood stages and segments of the mitochondrial cytochrome b (cyt b) gene. The most distinctive features of H. jenniae development are the circumnuclear gametocytes occupying all cytoplasmic space in infected erythrocytes and the presence of advanced, growing gametocytes in which the pellicle is closely appressed to the erythrocyte envelope but does not extend to the erythrocyte nucleus. This parasite is distinguishable from Haemoproteus larae, which produces similar gametocytes and parasitizes closely related species of Laridae. Haemoproteus jenniae can be distinguished from H. larae primarily due to (1) the predominantly amoeboid outline of young gametocytes, (2) diffuse macrogametocyte nuclei which do not possess distinguishable nucleoli, (3) the consistent size and shape of pigment granules, and (4) the absence of rod-like pigment granules from gametocytes. Additionally, fully-grown gametocytes of H. jenniae cause both the marked hypertrophy of infected erythrocytes in width and the rounding up of the host cells, which is not the case in H. larae. Phylogenetic analyses identified the DNA lineages that are associated with H. jenniae and showed that this parasite is more closely related to the hippoboscid-transmitted (Hippoboscidae) species than to the Culicoides spp.-transmitted (Ceratopogonidae) species of avian hemoproteids. Genetic divergence between morphologically well-differentiated H. jenniae and the hippoboscid-transmitted Haemoproteus iwa, the closely related parasite of frigatebirds (Fregatidae, Pelecaniformes), is only 0.6%; cyt b sequences of these parasites differ only by 1 base pair. This is the first example of such a small genetic difference in the cyt b gene between species of the subgenus Haemoproteus. In a segment of caseinolytic protease C gene (ClpC), genetic divergence is 4% between H. jenniae and H. iwa. This study corroborates the conclusion that hippoboscid-transmitted Haemoproteus parasites infect not only Columbiformes birds but also infect marine birds belonging to Pelecaniformes and Charadriiformes. We conclude that the vertebrate host range should be used cautiously in identification of subgenera of avian Haemoproteus species and that the phylogenies based on the cyt b gene provide evidence for determining the subgeneric position of avian hemoproteids.

Morphometrics of the eyes and orbits of the nocturnal Swallow-tailed Gull (Creagrus furcatus)

The Swallow-tailed Gull ( Creagrus furcatus (Neboux, 1846)) is known for its nocturnal feeding habits and apparently large eyes. Despite frequent observations of its large eyes, detailed measurements of its eyes and orbits are wanting. Here, we provide a detailed analysis of the size and shape of the eye and orbits of this unique species in relation to a range of other gull species. Although the C. furcatus does have a slightly enlarged cornea and optical axis, neither the transverse orbit diameter nor the shape of its eye differs significantly from other larids. In addition, we found no significant difference between C. furcatus and other gulls in terms of its orbit dimensions and orbit orientation. We therefore conclude that C. furcatus does not possess a transversely enlarged eye, but rather a slightly larger cornea and longer eye. Our results do not, however, preclude the presence of other changes in the visual system, such as retinal morphology or neurophysiology, that could be adaptive for nocturnal feeding.

Do night-active birds lack daily melatonin rhythms? A case study comparing a diurnal and a nocturnal-foraging gull species

Plasma melatonin concentrations in most animals investigated so far increase at night regardless of whether individuals are day or night active. Nevertheless, daily melatonin amplitudes are often seasonally adjusted to ecological conditions, with birds that breed at high latitudes and migrate during the night showing lower daily amplitudes. Here we investigate whether nocturnal seabirds, gulls that feed at night, also show a low melatonin amplitude because they have to be active predominantly during the night but also intermittently during the day. We sampled free-living nocturnal-foraging swallow-tailed gulls (Creagrus furcatus) on two Galapagos islands every ~4 h and compared their plasma melatonin concentrations with those of related black-headed gulls (Larus ridibundus) sampled in the Netherlands. Like most seabirds, the black-headed gulls showed generally low melatonin concentrations, but clear diel cycles. The swallow-tailed gulls, on the other hand, had similarly low absolute melatonin concentrations, but no detectable diel changes. Despite problems inherent in comparisons between two species and field/lab setups, our data lend support to the hypothesis that the lack of a diel melatonin rhythm allows animals to be active at any time.

A new synonymy and new records ofQuadraceps(Insecta: Phthiraptera: Philopteridae) from the Galápagos Islands

Abstract Nirmus paludicola Kellogg and Kuwana, 1902, now Quadraceps paludicola (Kellogg and Kuwana, 1902), is proposed as a senior synonym of Quadraceps ernstmayri Timmermann, 1952 (new synonymy). The host‐louse association between Q. paludicola and its type host, Butorides sundevalli (Reichenow, 1877), is discussed and deduced to be erroneous. The swallow‐tailed gull, Creagrus furcatus (Néboux, 1842), from the Galápagos Islands is regarded as the regular host for Q. paludicola and is also the type host of Q. ernstmayri. Eight further species and subspecies of Quadraceps are reported from the Galápagos Islands for the first time, and are included in an annotated checklist together with all Quadraceps taxa previously known from those islands.

Synchronization of Breeding and Intraspecific Interference in the Carrion Crow

DARLING (1938) suggested that synchrony of laying in colonial birds is stimulated by between birds, and larger colony, greater stimulus. Hence laying in larger colonies will be more synchronized than that in small ones. In Darling's words, the degree of breeding synchrony by stimulation may be densityrelated (Darling 1938: 53). Since then various authors have examined these ideas for different species of birds. Some students found such density correlated onset of laying to occur (Coulson and White 1960 in Black-legged Kittiwake, Rissa tridactyla; Horn 1970 in Brewer's Blackbird, Euphagus cyanocephalus; Nelson 1967 in Gannet, Morus bassana), while others found that they could not confirm phenomenon in various species of gulls, Larus [spp.] (MacRoberts and MacRoberts 1972 in L. argentatus and L. fuscus; Vermeer 1963 in L. glaucescens; Weidmann 1956 in L. ridibundus). In addition to these observations, Ashmole (1963), Hailman (1964), and Harris (1970) suggested that display interaction or social stimulation' cause breeding synchrony in some 'non-annual breeders (the Sooty Tern, Sterna fuscata, and Swallow-tailed Gull, Creagrus furcatus, respectively). Darling (1938) suggested that synchronous laying decreased predation, and Brown (1967), Parsons (1971), Patterson (1965), and Kruuk (1964) proved that Herring, Lesser Black-backed, and Black-headed Gulls (Larus argentatus, L. fuscus, and L. ridibundus respectively) that breed at peak of breeding season had better breeding success than individuals that breed earlier or later than peak. Patterson (1965) also showed that Black-headed Gulls that breed outside or on edge of a colony were more vulnerable to predation and thus less successful than birds in center. Edge effect (i.e. lower breeding success on edge of a colony) was reported for Gannet (Nelson 1967) and kittiwake (Coulson and White 1956). Horn (1968) found that clumped nesting in Brewer's Blackbird improves foraging efficiency and predation avoidance only when colony is built in a large expanse of nesting habitat, surrounded by abundant, but patchily distributed, food. All species mentioned breed in dense colonies, where distance between closest nest is rarely more than a few meters, but there is no reason why territorial species should not synchronize breeding in order to benefit in way that some colonial birds do. For example,

Egg-Eating by Galápagos Mockingbirds

The Galapagos mockingbirds (Mimidae) belong to the endemic genus Nesomimus, and it is generally accepted that there are four distinct species: N. trifasciatus (on Champion and Gardner-by-Floreana), N. melanotis (on San Crist6bal [= Chatham]), N. macdonaldi (on Hood [= Espafiola]), and N. parvulus -seven subspecies on different islands not inhabited by any of the other species (Swarth, Occas. Papers Calif. Acad. Sci. 18:1, 1931). It is therefore of some interest that Hatch (Condor 67:354, 1965) reports that only one species, N. macdonaldi, feeds on seabird eggs. N. trifasciatus and N. parvulus he found did not, and he does not mention N. melanotis, and says that is an interesting example of a behavior pattern differing strikingly between closely related species. On Hood Island N. macdonaldi, which has by far the largest bill of any of the species, is frequently seen attacking the unincubated eggs of the Galapagos Albatross (Diomedea irrorata), Blue-footed Booby (Sula nebouxii), Masked Booby (S. dactylatra), and Swallow-tailed Gull (Creagrus furcatus). L6veque (Alauda 32:5, 1964) reports these mockingbirds as eating the eggs of the American Oystercatcher (Haematopus palliatus), and on several instances I have seen them take the eggs of the Galapagos Dove (Zenaida galapagoensis). However, in the normal course of events it is unlikely that many eggs of any of these species are available to the mockingbirds except when extreme adverse conditions, such as food shortage or human interference, drive the birds from the nests. Also it must be only infrequently that the birds manage to crack an intact egg of the larger seabirds, although they would soon devour a hatching or cracked egg. Alan Root tells me that in 1966 the mockingbirds were pecking at bleeding wounds on the feet of the albatrosses. The mockingbird on Tower Island (N. parvulus bauri) was noted by Hatch (op. cit.) to be indifferent to the eggs of the abundant seabirds and even to freshly broken eggs. However, during field work on Tower Island in 1966-67, it was seen that this species would eagerly eat eggs of the Red-footed Booby (S. sula) and frigatebirds (Fregata minor) broken by other frigates or Lava Gulls (Larus fuliginosus) and would even peck furiously at unattended frigratebird eggs and try to eject them from the nests when the adults were scared away by human intruders in the colony (fig. 1). There is on Tower Island an extremely large colony of the Wedge-rumped Storm-Petrel (Oceanodroma tethys) which lays eggs in the large but well-protected open spaces under the lava flows. Large numbers of broken eggs are found near the nest sites, and Nelson (Ibis 108:430, 1966) thought that these had not been eaten by mockingbirds (he infers by the use of the abbreviation Nesomimus spp. that there is more than one species present, but there is no evidence for this) but were more likely a result of interspecific competition for nest sites. Close inspection of the colony, however, has now shown that the majority of these eggs have been ejected by competition (but intraspecific) and then eaten by mockingbirds. Great care had to be taken while examining petrel nests as the ?~

The Breeding Behaviour of Sabine's Gull, Xema Sabini

[Sabine's Gull, Xema sabini is a morphologically aberrant gull, breeding in the Arctic. This paper describes its breeding behaviour, as recorded in the region of Hooper Bay, W. Alaska (61° 35' N, 166° 05' W) in the summer of 1960. The object of this study has been, not just to describe the behaviour, but to try to relate it to the species' ecology, and also, by comparisons with other gulls, to clarify the taxonomic position of Sabine's Gull. Much of Sabine's Gull behaviour is similar to that of other gulls, but there are some aberrancies which occur either rarely or not at all in other species. Chief among these are the Quarter Upright, the emphasis on Hunched, as opposed to Upright, postures, the attraction of unmated females by Arch-and-Bow rather than Long Call, the direct feeding (as opposed to regurgitation) of the female early in the season, the rarity of Head Tossing in courtship feeding and copulation, and the throwback and Crouch in the Long Call postures. Evidently, Sabine's Gull is behaviourally as well as morphologically aberrant. It seems to be most closely related to such species as Franklin's Gull, Larus pipixcan. Contrary to MOYNIHAN'S (1959) suggestion, based on morphological criteria, there is no evidence of any relationship with the Swallowtailed Gull, Creagrus furcatus. The functions of the grey and black hood are discussed. It is also suggested that some of Sabine's Gull's morphological and behavioural peculiarities may be related to its breeding in small, loose groups rather than in dense colonies, on the flat tundra, and during the short Arctic summer. A partial analysis of the motivation of the agonistic and sexual behaviour was also made. The relations of the various agonistic postures to the tendencies to flee and attack are discussed. It is also concluded that the different postures adopted during the loud-calling phase of the Long Call depend on the position of the opponent and not on any motivational differences. The sexual behaviour seems to consist of two relatively independent systems - the Meeting Ceremony and Luring. The interrelationships of the different patterns in Luring are analysed in more detail., Sabine's Gull, Xema sabini is a morphologically aberrant gull, breeding in the Arctic. This paper describes its breeding behaviour, as recorded in the region of Hooper Bay, W. Alaska (61° 35' N, 166° 05' W) in the summer of 1960. The object of this study has been, not just to describe the behaviour, but to try to relate it to the species' ecology, and also, by comparisons with other gulls, to clarify the taxonomic position of Sabine's Gull. Much of Sabine's Gull behaviour is similar to that of other gulls, but there are some aberrancies which occur either rarely or not at all in other species. Chief among these are the Quarter Upright, the emphasis on Hunched, as opposed to Upright, postures, the attraction of unmated females by Arch-and-Bow rather than Long Call, the direct feeding (as opposed to regurgitation) of the female early in the season, the rarity of Head Tossing in courtship feeding and copulation, and the throwback and Crouch in the Long Call postures. Evidently, Sabine's Gull is behaviourally as well as morphologically aberrant. It seems to be most closely related to such species as Franklin's Gull, Larus pipixcan. Contrary to MOYNIHAN'S (1959) suggestion, based on morphological criteria, there is no evidence of any relationship with the Swallowtailed Gull, Creagrus furcatus. The functions of the grey and black hood are discussed. It is also suggested that some of Sabine's Gull's morphological and behavioural peculiarities may be related to its breeding in small, loose groups rather than in dense colonies, on the flat tundra, and during the short Arctic summer. A partial analysis of the motivation of the agonistic and sexual behaviour was also made. The relations of the various agonistic postures to the tendencies to flee and attack are discussed. It is also concluded that the different postures adopted during the loud-calling phase of the Long Call depend on the position of the opponent and not on any motivational differences. The sexual behaviour seems to consist of two relatively independent systems - the Meeting Ceremony and Luring. The interrelationships of the different patterns in Luring are analysed in more detail.]

Breeding Behaviour of the Swallow-Tailed Gull in the Galapagos

AbstractThe calls and displays of the swallow-tailed gull (Creagrus furcatus) are described and fitted into the pattern of larid displays; some ecological aspects of reproductive behaviour are briefly described. 1. The striking vocabulary includes a scream, snore, rattle and whistle. There is a 'long call' apparently homologous with the generalised gull long call and a special call associated with downward choking. 2. Swallow-tailed gulls breed in relatively small groups, the reproductive activities of the population of any island being highly unsynchronised, though those of the group significantly more so. The 'local' synchronisation is probably socially facilitated. 3. Fighting is rare, but includes a twisting movement reminiscent of the kittiwake's (Rissa tridactyla) cliff-adapted method. 4. Threat gaping is shown. 5. The oblique postures may be separated into (a) the retracted oblique (probably not equivalent to the generalised forward oblique of some other gulls) (b) a low oblique (probably homologous with the generalised oblique of other gulls). 6. A downward jerking movement may be a form of long calling and swallow-tails show a backward head jerk in closequarter territorial encounters. 7. An aggressive upright may be distinguished from an anxiety upright. 8. Upward choking (as in the kittiwake, but not in other gulls) and downward choking occur; both forms are hostile displays on the nest site. 9. The butterfly flight is probably strictly an intra-pair display and is associated with snore-scream calls. It may be related to the soar-and-swoop of the black-headed gull (Larus ridibundus), which is probably ritualised pursuit flight. 10. In the swallow-tail foot-looking is commonly associated with agonistic behaviour. 11. Courtship feeding of female by male is a regular part of pre-laying pair behaviour as in other larids. 12. Pre-copulatory behaviour is accompanied by head tossing. 13. Nest building is accompanied by long bouts of nest site calling. The nest is architecturally functionless. 14. The single egg (incubation period 35 days and incubation stint about 24 hrs) produces a highly cryptic chick. 15. Egg shells are not systematically removed. 16. The chick may accompany its parents some distance from the site in the first 48 hours after hatching. 17. Squids form a large part of its diet. The position of the swallow-tailed gull with respect to other larids is tabularised and discussed.

THE BREEDING CYCLE OF THE SWALLOW‐TAILED GULL CREAGRUS FURCATUS

IbisVolume 109, Issue 1 p. 14-24 THE BREEDING CYCLE OF THE SWALLOW-TAILED GULL CREAGRUS FURCATUS D. W. Snow, D. W. Snow British Trust for Ornithology, Tring, HertsSearch for more papers by this authorB. K. Snow, B. K. Snow British Trust for Ornithology, Tring, HertsSearch for more papers by this author D. W. Snow, D. W. Snow British Trust for Ornithology, Tring, HertsSearch for more papers by this authorB. K. Snow, B. K. Snow British Trust for Ornithology, Tring, HertsSearch for more papers by this author First published: January 1967 https://doi.org/10.1111/j.1474-919X.1967.tb00003.xCitations: 16 Contribution No. 65, Charles Darwin Foundation for the Galapagos. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume109, Issue1January 1967Pages 14-24 RelatedInformation

Dusky and Swallow-Tailed Gulls of the Galapagos Islands

Dusky and Swallow-Tailed Gulls of the Galapagos Islands