Specialization to cold‐water upwellings may facilitate gene flow in seabirds: new evidence from the Peruvian pelican Pelecanus thagus (Pelecaniformes: Pelecanidae)

Recent research has shown that tropical seabirds specialized to feed on cold water upwellings exhibit low population genetic differentiation and high gene flow across large geographic distances. This pattern is opposite to the general pattern of differentiation reported for tropical seabirds, and led us to hypothesize that specialization to cold‐water upwellings facilitates gene flow between colonies. As a test of this hypothesis we characterized population differentiation and gene flow across the range of the Peruvian pelican Pelecanus thagus, an upwelling specialist endemic to the Humboldt Current, using an 838 base pair segment of the mitochondrial control region and seven microsatellite loci. In support of our hypothesis we report genetic panmixia across the geographic range of this species and inferred high gene flow between colonies. The high dispersal propensity of upwelling specialist seabirds (adults and/or juveniles) may reduce loss of genetic diversity during population declines, and increase the ability of these species to colonize new islands.     

Aufzucht von Chilemeerespelikane (Pelecanus occidentalis thagus) im Vogelpark Walsrode mit Vergleichen zu anderen publizierten Erfahrungen mit Pelikanen

The probable world first captive breeding success in Chilean Brown Pelican (Pelecanus occidentalis thagus) in captivity is reported. Two chicks were hand reared at Walsrode Birdpark, Germany in 2006. Parents were imported in October 2005 and were wild birds that had been injured and subsequently rescued. All 10 adult birds demonstrated detrimental and chronically handicaps. First eggs were laid in January 2006. Eggs were incubated artificially at 37.1 °C and 56% rel. humididty. Two chicks hatched after 33 days of incubation. First feeding was made one day after hatching in the morning. Food was given 5 times a day. Until the 8th day after hatching, exclusively cut naked baby rats were fed. For stimulating the digestion and providing a good intestinal flora Lactobacillus powder was used and food was warmed up before application. After 8 days the diet was changed to fish. For development see figures. Worth to mention is the black-purple colour of the freshly hatched chicks which became successively paler with age. Also the development of the feather areas is characteristic for this (sub)-species. Taxonomy is discussed with some morphological arguments that are typical for subspecies. Nevertheless, some indications of possible breeding barriers between subspecies could support the suggestions for species status. Hatching and rearing data are compared with dates from other zoos and species of pelicans. The good development of the Walsrode birds based on the data and methods described leaves this article useful as a reference guideline for hand rearing pelicans.     

Use of temperature sensors to monitor patterns of nocturnal desertion by incubating Common Terns

ABSTRACT.   Adult Common Terns ( Sterna hirundo ) reportedly respond to nocturnal predation by deserting colonies from the time of disturbance until dawn the following morning. However, direct evidence for this behavioral response is limited because the nocturnal behavior of individual terns is difficult to monitor due to low visibility and the vulnerability of terns to disturbance at night. We monitored the nocturnal incubation behavior of 10 pairs of nesting Common Terns using continuously recording temperature sensors disguised in dummy eggs and placed in the nests. Changes in egg temperature during the night suggested that a range of desertion behaviors occurred in response to visits by a Great Horned Owl ( Bubo virginianus ) that preyed on chicks and adult terns. As many as three desertion events (desertion at one or more nests in a single 12-min period) were detected on a single night and nests were unattended for an average of 54 min (range 8–352 min) per desertion event. Nest temperature sensors allowed us to detect individual responses to nocturnal predators and to determine that desertion behavior was more varied than previously assumed. Desertion events were most frequent when physical evidence indicated the presence of an owl in the colony and during nights after owl predation, suggesting that desertion is a response to the actual risk of predation as well as to the possibility of predation.     

Distribution and foraging behaviour of the Peruvian Booby (Sula variegata) off northern Chile

The Peruvian Booby (Sula variegata) is one of the most numerous guano bird species in the Humboldt Current. We used a combination of data logger deployment, at-sea observations and colony-based work to investigate the foraging and diving behaviour, as well as the at-sea distribution and food choice of Peruvian Boobies breeding at Isla Pajaros, northern central Chile. Birds foraged in the vicinity of Isla Pajaros. They performed short foraging trips, varying between a few minutes and several hours. Average foraging range was 17.1 ± 3.5 km and diving took place between 2 and 10 km off the coast. Birds dived to depth of up to 10 m with an average depth of 4.3 ± 1.5 m. By at-sea observations as well as by data logger deployment, we identified important foraging areas close to the coast, especially around protruding points. The birds’ diet was highly variable between years, with Inka scad (Trachurus murphyi) and anchovy (Engraulis ringens) being the overall dominant prey species. Despite limited sample sizes, this paper presents first results about the foraging behaviour of Peruvian Boobies at the largest breeding colony in northern Chile. This information is essential for a better understanding of the effects of environmental changes as well as for the implementation of conservation measures.     

Patterns of foraging and range use by three species of neotropical primates

This paper describes the diet and range use patterns of the three species of primates in Santa Rosa National Park, Costa Rica (Ateles geoffroyi, Alouatta palliata, andCebus capucinus) and examines the variation in these variables as they relate to seasonal changes and concomitant changes in food availability. These three primate species were studied over a four-year period for a total of 24 months in the field. Santa Rosa National Park is in an area that experiences a long severe dry season in which little if any rain falls and the majority of the non-riparian trees lose their leaves. However, even though the three species were very flexible in terms of diet and range use, the behavioural variability did not correspond to changes in food availability or season.     

New records of Peruvian Mikania (Compositae)

Mikania macrostipulata sp. nov. is described, illustrated, and discussed.Mikania dioscoreoides, M. sprucei, andM. trifolia are reported new to Peru. The heterogeneity of the type material ofM. stereodes is also discussed.     

Enhanced luteinizing hormone release by luteinizing hormone-releasing hormone in incubating female turkeys (Meleagris gallopavo)

To determine what role pituitary responsiveness plays in the suppression of gonadotropin level during incubation in the turkey, the ability of the pituitary to release luteinizing hormone (LH) in response to luteinizing hormone-releasing hormone (LHRH) was compared in incubating, laying, and photorefractory birds. In all three groups, the i.m. injection of LHRH (4 micrograms/kg) increased serum LH levels; however, the LH response was markedly enhanced in the incubating turkeys as compared with the laying (6.6-fold increase over preinjection levels vs. 1.9-fold; p less than 0.05) or the photorefractory birds (9.7-fold vs. 3.1-fold; p less than 0.05). The LHRH-induced LH release was also determined in turkeys as they shifted from the laying to the incubating phase of the reproductive cycle. This response increased (p less than 0.05) in magnitude as the birds started to incubate. The high prolactin level of incubating turkeys does not have a depressing effect on LHRH-stimulated LH release; thus, impaired LH response to LHRH is not a mechanism involved in the diminished gonadotropin secretion of incubating turkeys.     

Control of actin moving trajectory by patterned poly(methylmethacrylate) tracks.

Poly(methylmethacrylate) (PMMA), a photoresist polymer, was found to be useful for immobilizing heavy meromyosin (HMM) molecules while retaining their abilities to support the movement of actin filaments. PMMA substrate was spin-coated on a coverslip, and various shapes of PMMA tracks, such as straight lines, concentric circles, and alphabetical letters, were fabricated by UV photolithography. An observation by a Tapping mode atomic force microscope (AFM) shows that the typical circular tracks were 1-2 microns wide and about 200 nm high. In in vitro motility assay, a solution of HMM molecules was applied to immobilize the molecules on the tracks by adsorption, and movement of actin filaments labeled with tetramethylrhodamine-phalloidin were observed in the presence of ATP by using an epifluorescence microscope and an image-intensified CCD camera. Actin filaments were seen to move precisely only on the PMMA tracks, and their traces drew the exact shapes of the tracks. The mean velocity of actin movement on the PMMA was 4.5 mm/s at 25 degrees C, and it was comparable to that on a conventionally used nitrocellulose film.     

GPS tracking reveals rafting behaviour of Northern Gannets (Morus bassanus): implications for foraging ecology and conservation

Capsule Three quarters of tracked Northern Gannets (Morus bassanus) at Grassholm gathered in rafts around the colony, concentrated within a recently designated at-sea Special Protection Area (SPA), but rafting was not correlated with foraging effort.

Aims To investigate the incidence, distribution and foraging implications of Northern Gannet rafting behaviour in waters adjacent to a large colony.

Methods Using bird-borne global positioning system (GPS) loggers we reconstructed at-sea movement and used a speed filter to identify rafting behaviour within 10?km of the colony. We mapped the spatial distribution of rafting events from 160 breeding individuals over 5 years, and investigated the relationship between foraging effort (trip duration and total distance travelled) and the presence/absence of rafting.

Results On average, 74% of tracked birds engaged in rafting. Of the 381 foraging trips analysed, rafting was recorded on 237 (62%). Birds were more likely to raft on outbound (224 trips, 59%), than inbound journeys (38 trips, 10%). Presence/absence of rafting did not correlate significantly with foraging trip distance or duration nor with duration of nest attendance. The majority of rafting was concentrated in a 2-km radius around the colony within a recently designated seaward SPA extension. Birds showed low individual repeatability in rafting, although there was lower variation within, than among, individuals.

Conclusion Our results show that rafting is important for breeding gannets on Grassholm, and a recently designated at-sea SPA encapsulates the core distribution of rafting. Rafting did not appear to be correlated with foraging behaviour. Given the dearth of literature on rafting and the wealth of GPS tracking data for seabirds, we suggest that similar research be conducted elsewhere to further elucidate the ecological and applied significance of this behaviour.     

The physiological state of captive and migrating Great White Pelicans (Pelecanus onocrotalus) revealed by their blood chemistry

The Great White Pelican Pelecanus onocrotalus is an endangered migratory bird, threatened by diminishing natural feeding sites and by persecution by fishermen. The majority of the migrating White Pelican (71000) stop-over in Israel during their autumn migration to Africa. As part of a larger study, aimed to assess the necessity of feeding during the stop-over in Israel, we examined the blood chemistry of captive and migrating White Pelicans. Blood was sampled from captive birds maintained on a fish diet, after food deprivation for 48 h and from wild birds brought from the field during migration. Food deprivation resulted in increased plasma levels of triglycerides and in lower levels of urea, potassium and calcium. In migrating birds, increased plasma levels of urea and CPK and lower levels of creatinine were revealed. In general, the coefficient of variation in the blood chemistry of migrating pelicans was higher than in the captive birds, that is to say, that these birds were in a variable physiological condition. The blood profile of migrating and wintering pelicans did not indicate a state of dehydration but did indicate energy deficiency. The less extreme changes in blood chemistry of the 48 h food-deprived compared to migrating pelicans suggest that the former did not reach a state of starvation. We conclude that for White Pelicans the stop-over in Israel is a must in order to rest and replenish their fuel reserves for completion of their autumn migration to Africa.     

Load size selection by foraging leaf-cutter ants (Atta cephalotes)

ABSTRACT.

• 1 Velocity of load-carrying Atta cephalotes (L.) foragers increases with increasing ant size and decreasing load size.
• 2 Foragers are selective in the sizes of loads they carry, but heavier loads would apparently increase their rate of leaf transport to the nest (mg of leaf m s^?1).
• 3 Even for very thin leaves, leaf diameter is not correlated with ant body size despite the method of cutting (rotating around a fixed point on the leaf edge).
• 4 When cutting leaves of different densities, load mass is more closely matched to ant size than is load surface area. This implies that ants choose loads based on mass rather than surface area, and thus the several possible disadvantages associated with carrying loads of large surface area (e.g. increased disturbance by wind or rain) are unlikely explanations of why ants do not select larger loads.
• 5 The relationship beween forager size and load size is made more complex by further selectivity at the level of colony recruitment: larger ants recruit to higher-density (thicker) leaf types.
• 6 Gross leaf transport rate is not maximized by foraging A.cephalotes, but net rate of energy intake cannot be assumed to follow the same pattern. If costs/time (not measured) are constant with changing load size, then the net rate of energy intake is not maximized. An alternative hypothesis is that costs/time increase with larger loads, thereby decreasing net rate of gain for larger loads.

     

Development and characterization of microsatellite loci in the American white pelican (Pelecanus erythrorhynchos)

We isolated and characterized nine microsatellite loci from the American white pelican, Pelecanus erythrorhynchos. The loci were screened in 23 individuals from the eastern and western populations of North America and were polymorphic, with the number of alleles per locus ranging from two to eight. Polymorphic information content ranged from 0.185 to 0.820 and observed heterozygosity from 0.217 to 0.957. These new loci will provide tools for studies of population structure in this species, thereby aiding conservation planning.     

A new Peruvian species of chiropterophilous Couepia (Chrysobalanaceae)

Couepia dolichopoda, a new bat-pollinated species from Amazonian Peru, is described and compared withC. longipendula, its nearest relative.     

Age differences in kleptoparasitism by laughing gulls (Larus atricilla) on adult and juvenile brown pelicans (Pelecanus occidentalis)

We recorded the choice of victims by a population of adult and first-winter laughing gulls (Larus atricilla) making attempts to steal food from adult and juvenile brown pelicans (Pelecanus occidentalis). Adult gulls made food theft attempts on juvenile pelicans with a disproportionately great frequency; first-winter gulls appeared to select pelican victims at random. Adult pelicans were more frequently successful in their foraging attempts than juvenile pelicans, suggesting that adults may be more reliable as potential food sources for gulls making theft attempts. However, juvenile pelicans attempted to evade kleptoparasitizing gulls less frequently than did adult pelicans, suggesting that the fish prey of juveniles may be more easily stolen. These patterns are discussed in relation to optimal victim choice by gulls, and to deferred maturity in both species.     

(Evolutionary) Theories of warfare in preindustrial (foraging) societies

I present an inventory of theories of war causation (and on the origin of war) in preindustrial (traditional, foraging, 'primitive', hunter-gatherer, band- and tribe-level) societies, with emphasis on the roles of natural selection, sexual selection and kin selection. Also the school of sociocultural evolution is briefly discussed.     

Green crab (Carcinus maenas) foraging efficiency reduced by fast flows

Predators can strongly influence prey populations and the structure and function of ecosystems, but these effects can be modified by environmental stress. For example, fluid velocity and turbulence can alter the impact of predators by limiting their environmental range and altering their foraging ability. We investigated how hydrodynamics affected the foraging behavior of the green crab (Carcinus maenas), which is invading marine habitats throughout the world. High flow velocities are known to reduce green crab predation rates and our study sought to identify the mechanisms by which flow affects green crabs. We performed a series of experiments with green crabs to determine: 1) if their ability to find prey was altered by flow in the field, 2) how flow velocity influenced their foraging efficiency, and 3) how flow velocity affected their handling time of prey. In a field study, we caught significantly fewer crabs in baited traps at sites with fast versus slow flows even though crabs were more abundant in high flow areas. This finding suggests that higher velocity flows impair the ability of green crabs to locate prey. In laboratory flume assays, green crabs foraged less efficiently when flow velocity was increased. Moreover, green crabs required significantly more time to consume prey in high velocity flows. Our data indicate that flow can impose significant chemosensory and physical constraints on green crabs. Hence, hydrodynamics may strongly influence the role that green crabs and other predators play in rocky intertidal communities.