Mitochondrial DNA suggests multiple colonizations of central Philippine islands (Boracay,Negros) by the sedentary Philippine bulbul Hypsipetes philippinus guimarasensis (Aves)

In this study, we have used fragments of three mitochondrial genes (Control Region, CR; transfer RNA for methionine, tRNA‐Met; NADH dehydrogenase subunit 2, ND2 for a total of 1066 bp) to reconstruct the phylogeographic history of the endemic Philippine bulbul (Hypsipetes philippinus) at the scale of the central area of the Philippine archipelago. The study includes two of the five recognized subspecies (guimarasensis and mindorensis), 7 populations and 58 individuals. Multiple phylogenetic and network analyses support the existence of two reciprocally monophyletic maternal lineages corresponding to the two named subspecies. Molecular clock estimates indicate that the split between the two subspecies is consistent with the Pleistocene geological history of the archipelago. Patterns of relationships within guimarasensis are biogeographically less clear. Here, a combination of vicariance and dispersal needs to be invoked to reconcile the molecular data with the geographical origin of samples. In particular, the two islands Boracay and Negros host mitochondrial lineages that do not form monophyletic clusters. Our genetic data suggest multiple independent colonization events for these locations.     

Vocal activity rate index: a useful method to infer terrestrial bird abundance with acoustic monitoring

Autonomous recording units have been widely used in a large number of bird studies in recent years, but challenges remain in estimating abundance based on acoustic monitoring. We tested whether vocal activity rate index (VAR; the number of songs per unit time for a species), recorded using autonomous recording units, was related to population abundance in two terrestrial bird species, the European Bee‐eater Merops apiaster and the Dupont's Lark Chersophilus duponti. We took recordings at sites where censuses were also carried out to estimate local populations around recorders. We found a positive and significant relationship for the two monitored species. Although our results are not conclusive, the strong and significant relationship found for both monitored species suggests that VAR may be used to infer bird abundance around recorders in terrestrial species. We describe five logical steps for using the VAR with autonomous recording units in other species to guide future studies.     

On the diet of the Pharaoh Eagle Owl,Bubo ascalaphus (Savigny, 1809), in Qatar,with an overview of its feeding habits

The diet of Bubo ascalaphus in Qatar was assessed based on pellets collected from the first known nesting site of the species in the country. The pellets contained a total of 68 prey items, representing 9 different species: 4 mammals, 1 bird, 1 reptile, and at least 3 scorpions. Mammals clearly comprised the major food source (89.7% and 97.7% in frequency and biomass respectively). Our data suggest that Pharaoh Eagle Owls are opportunistic predators that feed on a variety of prey depending on their temporal/spatial availability, which is consistent with previous studies. A literature review clearly suggests that Eagle Owls in arid to semi-arid environments are opportunistic predators with small mammals being their main prey. Predation on migrating Blue-cheeked Bee-eaters Merops persicus supports this hypothesis.     

All you can eat: is food supply unlimited in a colonially breeding bird?

Food availability is generally considered to determine breeding site selection and therefore plays an important role in hypotheses explaining the evolution of colony formation. Hypotheses trying to explain why birds join a colony usually assume that food is not limited, whereas those explaining variation in colony size suggest that food is under constraint. In this study, we investigate the composition and amount of food items not eaten by the nestlings and found in nest burrows of colonially nesting European bee‐eaters (Merops apiaster). We aimed to determine whether this unconsumed food is an indicator of unlimited food supply, the result of mistakes during food transfer between parents and chicks or foraging selectivity of chicks. Therefore, we investigated the amount of dropped food for each nest in relation to reproductive performance and parameters reflecting parental quality. Our data suggest that parents carry more food to the nest than chicks can eat and, hence, food is not limited. This assumption is supported by the facts that there is a positive relationship between dropped food found in a nest and the number of fledglings, nestling age, and chick health condition and that the amount of dropped food is independent of colony size. There is variation in the amount of dropped food within colonies, suggesting that parent foraging efficiency may also be an important determinant. Pairs nesting in the center of a colony performed better than those nesting on the edge, which supports the assumption that quality differences between parents are important as well. However, dropped food cannot be used as an indicator of local food availability as (1) within‐colony variation in dropped food is larger than between colony variation and, (2) the average amount of dropped food is not related to colony size.     

Migration by soaring or flapping: numerical atmospheric simulations reveal that turbulence kinetic energy dictates bee-eater flight mode

Aerial migrants commonly face atmospheric dynamics that may affect their movement and behaviour. Specifically, bird flight mode has been suggested to depend on convective updraught availability and tailwind assistance. However, this has not been tested thus far since both bird tracks and meteorological conditions are difficult to measure in detail throughout extended migratory flyways. Here, we applied, to our knowledge, the first comprehensive numerical atmospheric simulations by mean of the Regional Atmospheric Modeling System (RAMS) to study how meteorological processes affect the flight behaviour of migrating birds. We followed European bee-eaters (Merops apiaster) over southern Israel using radio telemetry and contrasted bird flight mode (flapping, soaring-gliding or mixed flight) against explanatory meteorological variables estimated by RAMS simulations at a spatial grid resolution of 250 × 250 m(2). We found that temperature and especially turbulence kinetic energy (TKE) determine bee-eater flight mode, whereas, unexpectedly, no effect of tailwind assistance was found. TKE during soaring-gliding was significantly higher and distinct from TKE during flapping. We propose that applying detailed atmospheric simulations over extended migratory flyways can elucidate the highly dynamic behaviour of air-borne organisms, help predict the abundance and distribution of migrating birds, and aid in mitigating hazardous implications of bird migration.     

云南怒江河谷栗喉蜂虎营巢地特征

2010年4～5月,对云南省保山市怒江河谷栗喉蜂虎营巢地进行了调查。共调查营巢地18个。对巢洞深度、断崖面积、巢区面积、坡度、裸露度、断崖与水域及公路的直线距离、巢区最上巢与崖顶距离、最下巢与地面距离、海拔、坡向等11个生态因子进行了测量。通过访谈法对营巢地所在断崖的形成年限进行了调查。此外还收集巢区和非巢区土壤18份,在实验室用沉淀法测量巢区和非巢区土质含沙量。结果表明,影响栗喉蜂虎营巢地选择的主要因子依次为巢区沙土含沙量、断崖新旧、巢区面积、裸露度、最下巢与地面距离、坡度。在营巢地选择时,栗喉蜂虎主要考虑掘巢难易程度和防御天敌等方面的因素。     

Determinants of between‐year burrow re‐occupation in a colony of the European bee‐eater Merops apiaster

Re‐occupation of existing nesting burrows in the European bee‐eater Merops apiaster has only rarely – and if so mostly anecdotically – been documented in the literature record, although such behavior would substantially save time and energy. In this study, we quantify burrow re‐occupation in a German colony over a period of eleven years and identify ecological variables determining reuse probability. Of 179 recorded broods, 54% took place in a reused burrow and the overall probability that one of 75 individually recognized burrows would be reused in a given subsequent year was estimated as 26.4%. This indicates that between‐year burrow reuse is a common behavior in the study colony which contrasts with findings from studies in other colonies. Furthermore, burrow re‐occupation probability declined highly significantly with increasing age of the breeding wall. Statistical separation of within‐ and between‐burrow effects of the age of the breeding wall revealed that a decline in re‐occupation probability with individual burrow age was responsible for this and not a selective disappearance of burrows with high re‐occupation probability over time. Limited duty cycles of individual burrows may be caused by accumulating detritus or decreasing stability with increasing burrow age. Alternatively, burrow fidelity may presuppose pair fidelity which may also explain the observed restricted burrow reuse duty cycles. A consequent next step would be to extend our within‐colony approach to other colonies and compare the ecological circumstances under which bee‐eaters reuse breeding burrows.     

Soil composition affects the nesting behavior of blue-tailed bee-eaters (Merops philippinus) on Kinmen Island

The blue-tailed bee-eater (Merops philippinus) is a summer migrant that breeds on Kinmen Island, located off the west coast of Taiwan, about 5 km from the southern coast of mainland China. The aim of this study was to investigate why blue-tailed bee-eaters build their nests in sandy loam and sandy clay loam, but not in clay loam. Soil chemical and physical properties, and mineralogical composition were measured for the different soil types. Clay loam had a significantly lower pH, Na, and base saturation than did sandy loam or sandy clay loam. Clay loam had a significantly higher N, cation-exchange capacity (CEC), K, and free iron (Fe_d) and aluminum oxide (Al_d) contents than the other soil types. Clay loam had significantly lower sand and higher clay content, and higher bulk density and penetration resistance than the other soil types. The correlation coefficients (r ²) between penetration resistance and Fe_d, Al_d, and clay contents were 0.997, 0.848, and 0.779, respectively. Soil strength and compaction are important criteria for bee-eaters nesting-site selection. The lower pH of clay loam would enhance the exchangeable Al and acidity, further increasing the soil aggregation. Thus, it might prevent the bee-eaters from excavating nesting burrows.     

Microsatellite loci in the European bee‐eater,Merops apiaster

Twelve polymorphic microsatellite markers have been developed for the European bee‐eater, Merops apiaster (Coraciiformes: Meropidae). Screening of eight individuals at these loci showed that the average allelic diversity was 5.8, with a range of two to 11 alleles per locus. The loci reported here will provide insight into the levels of extra‐pair parentage, kin selection and dispersal in this species, which has co‐operative breeding and nests in large colonies.     

Use of novel nest boxes by carmine bee‐eaters (Merops nubicus) in captivity

Carmine bee‐eaters make attractive additions to zoo aviaries but breeding programs have had challenges and limited success. The objectives of this study were to document nesting behavior of Carmine bee‐eaters in a captive setting and compare reproductive success between a novel nest box (plastic, 17 × 30 × 22 cm) and a PVC pipe model used previously (30 cm long, 8 cm in diameter). Three bee‐eater pairs were given access to seven nest chambers (six novel boxes, one PVC model). Behavioral observations occurred during a 15‐min period in the morning or afternoon before egg production and continued until chicks fledged for a total of 87 observation periods (21.75 hr). All occurrences by an individual bird entering or exiting a nest tunnel, food provision, and the time (min) spent inside a nest cavity were documented. Additionally, daily temperature within each nest chamber was recorded. Before eggs were produced the average daily temperature (23.02°C) within the nest chambers did not differ, suggesting that nest cavity choice was not influenced by temperature. No differences were detected among pairs in percent of observed time spent inside their nest cavities or number of times a nest tunnel was entered during the incubation or fledging periods. During incubation females spent a greater percent of observed time inside the nest cavity than males (P=0.02). During the fledging period food provision did not differ between the pairs, however males entered their nest tunnels more often per hour than females (P=0.03), and males tended to provide food more often than females (P=0.053). Two pairs nested in novel nest boxes and successfully fledged one chick each. The pair that nested in the PVC model did not fledge a chick. A nest box that aids in keeping eggs intact is essential for breeding bee‐eaters in captivity, and maintaining captive populations will provide opportunities for zoo visitors to enjoy these birds and will reduce the need to remove birds from the wild. Zoo Biol 0:1–13, 2007. © 2007 Wiley‐Liss, Inc.