Observations of Brown-Throated Martin Riparia paludicola Nesting and Roosting in Burrows of European Bee-Eaters Merops apiaster

The European bee-eater (Merops apiaster) migrates through Saudi Arabia annually. A total of 25 individuals of this species were captured from three localities in Riyadh and Ta'if. Three species of chewing lice were identified from these birds and newly added to list of Saudi Arabia parasitic lice fauna from 160 lice individuals, Meromenopon meropis of suborder Amblycera, Brueelia apiastri and Meropoecus meropis of suborder Ischnocera. The characteristic feature, identification keys, data on the material examined, synonyms, photo, type and type locality are provide to each species.

Animals frequently host organisms on their surface which can be beneficial, have no effect or a negative effect on their host. Ectoparasites, by definition, are those which incur costs to their host, but these costs may vary. Examples of avian ectoparasites are chewing lice which feed exclusively on dead feather or skin material; therefore, costs to their bird hosts are generally considered small. Theoretically, many possible proximate effects exist, like loss of tissue or food, infected bites, transmission of microparasitic diseases or reduced body insulation due to loss of feathers, which may ultimately also have fitness consequences. Here, we experimentally examined a possible negative impact of 2 feather-eating louse species (Meropoecus meropis and Brueelia apiastri) on male and female European bee-eaters (Merops apiaster) by removing or increasing louse loads and comparing their impact to a control group (lice removed and immediately returned) after 1 month. A negative effect of chewing lice was found on body mass and sedimentation rate and to a lesser extent on haematocrit levels. Males and females lost more weight when bearing heavy louse loads, and were more susceptible to infestations as indicated by the higher sedimentation rate. Our results further suggest differences in sex-specific susceptibility.

The Information Centre Hypothesis (ICH) and the Two-Strategies Hypothesis (TSH) predict that foraging success is enhanced by information exchanged among individuals within a colony or roost. Nest location within a colony may be critical in this regard, as individuals with abundant, nearby neighbours likely have greater access to information regarding a new food resource than relatively isolated breeders. To determine how the availability of neighbours influences information transfer, we quantified foraging success in a population of European bee-eaters (Merops apiaster) provided with a honey bee (Apis mellifera) hive as a new food resource. To quantify potential information transfer we developed a neighbour index that incorporated both the number and proximity of neighbours into a single continuous measure. The change in feeding rate of individual birds after introducing the honey bee hive was positively correlated with our neighbour index, suggesting that information transfer among colony members, at least in part, selects for colonial breeding in European bee-eaters.

The evolution of coloniality is usually explained by a benefit/cost ratio greater than one. Alternatively, when costs exceed benefits, a clumped or restricted availability of limiting resources is used to explain coloniality. In this study we examine the relation between reproductive success and colony size in the European bee-eater (Merops apiaster). In our study population in Slovakia colony size varied from solitary breeding pairs up to 79 pairs per colony. We found no seasonal effects on reproductive success, however, there was a negative correlation between colony size and chick condition and survival. This relationship, although not significant, tended to be the same when examining only the earliest breeding pair of each colony site. There was no relation between reproductive parameters and age of parents and no indication for age related settlement or any effect of the nest hole position within a colony. Limitation of nesting sites and distribution of food are probably two important determinants for colonial breeding in this species. Different aspects, including the rare occurrence of helpers, are discussed as possible factors explaining the negative relationship between annual reproductive success and colony size.

Successful breeding of the European Bee-eater Merops apiaster at ca 1200 m elevation in Valais (southwestern Swiss Alps) In 2018, the European Bee-eater bred at 1165 m above see level on a South-exposed slope of the Upper Rhone Valais (southwestern Swiss Alps). At least four juveniles fledged, from apparently one single occupied breeding hole. The landscape is dominated by cultivated grasslands and hedges, and surrounded by xeric, sub-Mediterranean oak and pine forests. To the best of our knowledge this represents a new altitudinal record for western Europe outside the Mediterranean basin.

Understanding the relationship between migratory performance and fitness is crucial for predicting population dynamics of migratory species. In this study, we used geolocators to explore migration performance (speed and duration of migratory movements, migratory timings) and its association with breeding phenology and productivity in an Afro-Palearctic insectivore, the European bee-eater (Merops apiaster), breeding in Iberian Peninsula. Bee-eaters migrated at higher travel speeds and had shorter travel duration in spring compared to autumn. Individuals that departed earlier or spent fewer days in-flight arrived earlier to the breeding areas. Our results show overall positive, but year-specific, linkages between arrival and laying dates. In one year, laying was earlier and productivity was higher, remaining constant throughout the season, while in the subsequent year productivity was lower and, importantly, declined with laying date. These results suggest that arriving earlier can be advantageous for bee-eaters, as in years when breeding conditions are favourable, early and late breeders produce high and similar number of fledglings, but when conditions are unfavourable only early breeders experience high productivity levels.

In this study we examine the population biology of Brueelia apiastri, a chewing louse living on the European bee-eater (Merops apiaster). We investigate the relationships between parasite intensity of infestation, sex ratio, reproductive output, parasite size and their environment i.e. the morphology, condition, age and sex of the host. Chewing lice were collected, their sex and age (developmental stage) identified and parasite body size determined as a measure of parasite condition (larger individuals consume larger meals and larger females may produce larger clutches). The data show that there is variation in intensity as well as body size of B. apiastri between individual bee-eaters and this variation is independent of the sex of the birds. However, size, condition and age of the birds seem to influence the infestation rates with B. apiastri. The study suggested size-dependent depredation, since more, smaller chewing lice (usually nymphs) living on birds in better condition and birds having longer bills. Furthermore, more male chewing lice (males are smaller than females) live on older birds. Intraspecific competition between parasites seems to have a negative effect on female but not male body size but this result could be also explained by size-dependent depredation.

Effect of European Bee-Eater (Merops Apiaster) on Honeybee Colonies in Toshka Region, Egypt

Helping-at-the-nest provides a classic example for the analysis of the costs and benefits of altruism in relation to kin selection. Most studies to date have relied on genealogical data obtained by ringing parents and offspring. However, growing evidence shows that both extra-pair copulations and intra-specific nest parasitism are sufficiently frequent in birds to produce patterns of relatedness that differ appreciably from those inferred from ringing studies. This could have major repercussions for calculations of the genetic costs and benefits of helping. We therefore used DNA fingerprinting, in conjunction with detailed field observations over eight years (1983–1990) to analyse the helping behaviour of European bee-eaters (Merops apiaster). Fingerprints of 11 unhelped (60 chicks) and 8 helped (40 chicks) families using 33.6, 33.15 and M13 probes showed that: (a) every chick from unhelped families could be correctly assigned to their putative parents; (b) helpers are invariably genetic relatives (r = 0.5) of one or both of the breeding pair they help; and (c) in a preliminary analysis of parentage in helped families, about 2% (1/40) chicks in helped nests are not sired by the putative father. The helper in this case did not appear to be the father, but the illegitimate offspring may have been sired by a close relative of the helper.

Capsule A combination of several biometric measures enables the reliable sexing of the European Bee-eater Merops apiaster, a species with subtle sex differences in plumage and morphometry. Aims To explore variation in biometrics and their suitability to discriminate sex in adult European Bee-eaters Merops apiaster. Methods We sampled populations of a long-distance migratory species with low sexual size dimorphism, the European Bee-eater Merops apiaster, from colonies in western Iberia (Portugal) and Central Europe (Germany) to investigate body size variation and derive population-specific and general sex discriminant functions. Results Overall, male Bee-eaters were larger than females while Bee-eaters from Germany and Portugal did not differ in size, except for primary length and tail length. The best single measurement to discriminate sex was wing length for Portuguese birds and tail tip length for German birds, as in the combined dataset. Multivariate discriminant functions of head-bill, wing and tail tip lengths provided the highest discriminant accuracy, discriminating sex for 91% of the birds from Portugal, 96% from Germany and 94% when using the combined dataset. Nonetheless, the discriminant accuracy remained high in the functions using only two variables for Portugal (head-bill and tail tip 91%, head-bill and wing 88%, wing and tail tip 88%), Germany (head-bill and tail tip 95%, wing and tail tip 97%) and in the combined dataset (head-bill and tail tip 92%, wing and tail tip 93%). Conclusions Population specific discriminant functions allow sexing of European Bee-eaters by morphometry with high degree of accuracy at least for Iberia and Central European populations. Such discriminant functions can be used to assign the sex of adult Bee-eaters reliably and swiftly while the bird is still in the hand, highlighting the potential of these functions for rapidly sexing species with low degrees of sexual size and plumage dimorphism.

Finding a balance between wildlife conservation and land use protection when conflicts arise requires applying measures based on scientific knowledge and applicability. This is because of the complexity of interactions and the social dimensions of human–wildlife relationships. One of the conflicts in the Mediterranean basin is between European bee-eaters Merops apiaster and beekeeping. The objective of this study was to evaluate the activity of bee-eaters in relation to honey bees Apis mellifera in Extremadura (W Spain), and the possible correlation with traits and viability of beehives. We also aimed to assess the effectiveness of damage prevention measures, to be able to predict whether they could assist in the future sustainability of apicultural management. A monitoring program was conducted in 58 apiaries to observe bee and bee-eater activity and abundance. Additionally, we measured the effect of environmental variables and the amount of resources in the hives, by means of honey, pollen, and brood. We found that bee-eater negatively correlated to honey bee activity and the more abundant it was the fewer resources (honey, pollen, and brood) and lower abundance of bees in the hives, mainly during their migratory season (August). However, there were no negative effects on the survival and viability of the hives. The preventive and deterrent measures offered promising results, especially the installation of shading meshes around the apiary that prevented the predation of bees in the immediate surroundings of the beehives. Further studies on the effectiveness of preventive techniques and their practical implementation through different mechanisms of economic compensation must be enhanced to reduce this social conflict.

Metacheyletia degenerata Fain and Bochkov, 2003 (Acariformes: Cheyletidae) is recorded for the first time from the quills of the European Bee-eater Merops apiaster L., 1758 (Coraciformes: Meropidae). It is also the first record of Metacheyletia found on coraciiform birds. Moreover, the following localities: Macedonia, Italy, Azerbaijan, Russia and Tanzania, are new for M. degenerata.

Aerial insectivorous birds depend highly on favourable weather conditions for successful foraging because flight activity of insects is constrained by daily weather. Thus, the variation in weather conditions during reproduction, mediated by prey limitations, should be mirrored in annual reproduction performance, and finally in annual breeding success. We analysed the effect of local weather conditions on the availability of airborne insects and on the variation in brood size and nestling condition of European bee-eaters Merops apiaster at the northern edge of their range where years with adverse weather frequently occur. The availability of large flying insects, the common prey of bee-eaters, increased with air temperatures and duration of daily sunshine. As predicted, local weather conditions affected reproductive performance with annual breeding success (mean 3.7 nestlings per breeding pair, range 1.7–4.9 nestlings) being up to 32 % higher in extraordinary dry and hot summers. Additionally, a nestling's body condition (residual mass) was also affected by sunshine duration during their growth period and internally was co-affected by the number of siblings and the individual rank within the sibling hierarchy. Thus, a prolonged duration of daily sunshine causes a cascade from higher insect flight activity, and, thus, higher food availability for chick-rearing bee-eaters, which finally translates into better chick body conditions and higher annual breeding success. Consequently reproduction and population development of European bee-eaters might be especially susceptible to regional changes in weather and climatic conditions.

Decision making in burrowing birds: Sediment properties in conflict with biological variables

The use of Autonomous Recording Units (ARUs) for wildlife monitoring has increased in recent years. Acoustic monitoring has been used for a wide range of research topics, but it has rarely been used for monitoring wildlife migrations. In this work we evaluate the use of acoustic monitoring to characterise the diurnal migration pattern of a bird species, the European Bee-eater Merops apiaster. We set up 3–4 acoustic monitoring stations daily from 11 August to 21 September 2017 in north-eastern Spain, during post-breeding migration of the species. We used the Vocal Activity Rate (VAR), defined as the number of calls per unit time, as an index of Bee-eater abundance to describe the daily and seasonal migration pattern of the species. We also assessed the relationship between daily mean VAR estimated by ARUs, with citizen science data uploaded to the platform Ornitho.cat over a large spatial scale. According to mean VAR, intensity of migration increased weekly until the last week of August when it peaked, with species abundance decreasing to the lowest values in the study area by late September. A significantly higher number of calls was detected in the first and last hours of the day. Our results agree with previously published seasonal and daily migration patterns described for the species. VAR was significantly, positively correlated with the percentage of citizen science records of Bee-eater uploaded to complete checklists, used as an independent source to compare migration timing. Overall, our results, validated through citizen science data, show that acoustic monitoring can effectively provide complementary data for monitoring the bird migration of vocally active species. The use of ARUs may help to improve our understanding of migratory behaviour and be useful for a wide range of purposes.