SPECIES

European Bee-eater Merops apiaster Scientific name definitions

Hans-Valentin Bastian and Anita Bastian
Version: 2.0 — Published January 14, 2022

Conservation and Management

European Bee-eater has an extremely large breeding distribution from western Europe to Mongolia and from the Iberian Peninsula to the Maghreb, Turkey to northern India, and with an isolated population in southern Africa. The breeding range covers an area approximately 55,700,000 km² (57), though recent range expansions at the northern edge of distribution are probably not adequately represented. It is considered Least Concern (57), as the breeding range does not reach the threshold of <20,000 km², nor has its population been declining by more than 30% over 10 years, to be considered Vulnerable. The global population, though likely overestimated in the past (675), is still very large at 3,160,000–6,400,000 individuals. Although the breeding status of the species is poorly known over large portions of its distribution, with few reliable data from the Caucasus, northern India, western China, Mongolia, parts of Russia, Turkey, the countries around the Aegean Sea, and the Maghreb, the species is considered common and widespread over much of its range (57). In Europe, the species is listed in Appendix II (Strictly protected fauna species) of the Convention on the Conservation of European Wildlife and Natural Habitats (694), as well as in the Appendix of the Convention on the Conservation of Migratory Species of Wild Animals (695).

Effects of Human Activity

Habitat Loss, Degradation, and Climate Change

Direct Habitat Destruction

Settlements built along the coasts, as well as and degradation and channelization of rivers, has destroyed extensive areas of breeding habitat. On Mallorca, significant reductions in suitable breeding habitats coincided with a population decline of 53% over 10 years; the deterioration of sand banks, which were used for nest sites, may have been particularly important in driving this decline. The remaining breeding sites were further threatened by development, reforestation, and a lack of colony stability (132). This has also been seen on the smaller neighboring island of Menorca, where the population decreased from the mid to late 1980s mainly due to habitat loss and deterioration, especially as a result of human pressure. Here, colonies located near the coast suffered a high desertion rate, with displacement to sandy areas inland and an increased tendency of nesting in the ground (133). When breeding does occur in manmade habitats, colonies could be lost due to filling of quarries, flattening of steep walls, or mining. Nest sites were also abandoned due to tree and shrub succession (673).

Climate Change and Biodiversity Loss

A major threat to bee-eaters is the progressive loss of insect biodiversity and biomass (e.g., 696, 697, 698). Whereas the population of bee-eaters has increased in Germany significantly over the past three decades, contemporaneously there has also been a 75% loss of insect biomass (696). Large-scale use of pesticides in Europe and Africa and the increase of large-scale agricultural monocultures are thought to be key causes for the insect collapse. Therefore, in central and western Europe, there has been a concern that if insect biomass losses continue, the current increasing trend of bee-eater populations would stop or even reverse. In Germany, it is thought that bee-eaters can only establish stable breeding colonies at localities where the insect loss is less severe, potentially explaining why its growing populations have been so patchily distributed (379, 699).

In addition to direct habitat destruction, recent climate change has also affected vegetation structure as well as insect diversity and abundance. While climate change has allowed bee-eaters to expand northward and to establish of new populations (601, 272, 116, 98, 167, 63), it may also be responsible for recent population declines around the Mediterranean and in South Africa (627, 690, 101, 130). In particular, loss of vegetation due to heat and drought can cause a reduction in food availability and habitat for insects, leading to declines in insect abundance, which can have a negative impact on breeding success in bee-eaters (e.g. 700, 701, 702). In the Caucasus, the numbers of migratory bee-eaters are steadily declining at the Caspian Sea, although they have also increased in the Caspian Depression of Daghestan. Arid conditions are discussed as one reason for the declines of European Bee-eaters along former major flyways, and the change to new migration routes (703). Although climate change is undoubtedly affecting bee-eater populations in the Mediterranean, high intensity land use may ultimately have a bigger impact on declines there (678).

Shooting and Trapping

Capture and killing of European Bee-eater is widespread around the Mediterranean as a source of food, for pleasure, or for sport. Thousands of bee-eaters are trapped, caught with lime-sticks or nets, and shot during their annual migration to and from non-breeding areas (672). Exact figures for how many bee-eaters are killed annually are not available, though in Cyprus, 3,000-5,000 have been killed annually (59), and in Lebanon (672), the Nile Delta, and along the Mediterranean coast of Egypt and Libya, thousands have been killed each year (59).

Bee-eaters and Beekeeping

In the fourth book of the Georgica, Virgil (70–19 BC) wrote that bee-eaters were to be kept away from beehives. Even today, beekeepers sometimes vehemently pursue them in order to protect their hives (e.g., 704, 705). Persecution has been reported from Europe, Africa, the Middle East, the Caucasus, and Asia. Bee-eaters are suspected to interfere with bee mating while foraging near hives (706, 705), and they feed on drones and worker-bees in significant numbers, reducing colony size (707, 500); bee-eaters can also predate honeybee queens, causing hive collapses (708). As a result, all bee-eaters, but especially European Bee-eater (668), are considered as pests in several countries and are shot (262, 409, 500, 709), captured with nest traps (430), or chased away (710). In countries where the species is under legal protection, it has been recommended, unrealistically, that colonies should be relocated (708). In India, no widespread measures against bee-eaters (and other bee-eating birds) are recommended (711), but some archaic methods are used to try and dissuade birds, including hanging dead bee-eaters near hives to scare them away, using noise or high-pitched sounds, or playing distress calls (710, 711), all of which have been unsuccessful in Turkey (430).

Despite the perceived threat that bee-eaters pose to hives by beekeepers, several studies have documented rather low levels of harm caused by bee-eaters (18, 712, 713, 469, 21, 714, 528, 709). In Rwanda, only 6% of beekeepers surveyed considered bee-eaters to be a problem (715). Bee-eaters also capture insects that in turn eat bees, such as hornets (Vespa crabro, Vespa orientalis), beewolves (Philanthus sp.), and Crabonid wasps (e.g., Cerceris sp), thus minimizing further losses in bee colonies (712, 716); in some locations, the consumption of hornets balanced the loss of honeybees (569, 711). Losses of bees to European Bee-eater have indeed been reported though, and depending on the location, losses range from 0.27% to 5.5% of a local bee population, corresponding to 2.7–7.3% of a hive's monthly reproductive output (469, 21, 717, 715); losses of 5–10% of the worker population in honeybees is considered acceptable (21). In Spain, one bee-eater captured on average 1,300 ± 760 bees during the entire breeding season, which correspond to the daily reproductive output of a single hive (716); a bee queen lays up to 1,500 eggs per day. In central Spain, honeybees accounted for 35–42% of the diet out of >10,000 prey sampled. This proportion increased to >70% when feeding nestlings in July and August (523). In Germany, it was determined that a bee-eater captured on average 20 bees per day (705). However, even with these bee losses, an economic loss in honey production could not be found in most locations (718, 705, 719), although a decrease in stored pollen was measured in Egypt (720); in northern Germany, during a period of adverse weather, bee hives were intensively exploited, so that several new honeybee colonies had to be purchased after the season (609).

Bee-eaters tend to have the greatest impact on beekeeping during migration. In Israel, the pollination of flowering melons and honeydews coincides with bee-eater migration, which forage at hives placed in the fields (409). Especially during migration, covering hives with a net, or placing them under a dense canopy, significantly reduced foraging around hives (710, 500, 528). To further mitigate bee-eater damage to hives, birds have also been captured and relocated at least 35 km away, where they were released at a location in the direction they were migrating (409). During the breeding season, it has been recommended to place hives at least 1 km from a bee-eater colony (718, 469, 721, 705, 714, 722), as bee-eaters have a limited foraging range around the colony (705, 383). Placing hives over a large area can also reduce the risk of predation by bee-eaters, though this is not practical if honeybees are primarily kept for crop pollination (21). In Libya, widely distributed hives reduced risk to worker bees, while hives that were clustered together in a small area experienced higher levels of predation (721). Hives also tend to be more intensively used as a food source during cloudy or rainy weather (487, 527, 247, 496, 18, 469, 89, 609, 82, 528), or even during extremely high temperatures in the southern portion of its range (528). Therefore, it has been recommended that hives are closed during bad weather conditions for safety, when bees are not very active anyway (469).

Hives located in an insect-rich environment reduces predation intensity on hives, as bee-eaters tended to disperse over a larger area (721, 719, 716). However, due to widespread declines in insect populations around the world (see Habitat Loss and Degradation, above), hives may be exploited more heavily in the future as they become a reliable source of food. See also Diet and Foraging.

Pesticides and Other Contaminants/Toxics

The effect of toxic metals on bee-eaters that breed in quarries is not fully understood. The concentrations of arsenic and 11 metals (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) in feathers and regurgitated pellets collected in southeastern Portugal were significantly higher in birds that bred at a mining site compared to those that did not, although there was not an observed direct effect on fitness (723).

Human/Research Impacts

Reactions to humans are usually quite different from reactions to predators, and depend primarily on the degree of habituation to people. Bee-eaters tend to be less shy when breeding near settlements, in actively managed quarries with regular contact with construction machinery, or in active vineyards. When bee-eaters are in regular close contact with people, the flight distances can drop to below 50 m 350, 361, 410,364, 724, 368, 162, 115). Nests next to birding lodges are not visibly disturbed by birders, even during busy periods at the blinds (H-VB, AB). Construction machines and the people inside driving them are usually ignored, but all people standing outside are perceived as a potential source of danger and trigger alarm behavior (480, 307, 356, 368). In Poland, however, machinery in quarries was avoided (113). Birds that breed away from quarries, or those that are not accustomed to humans, however, are usually shy, with flight distances of up to 300 m (224, 334, 410, 631, 256, 175, H-VB, AB). Disturbances at these colonies cause an immediate stop to feeding, with adults perching near the burrow with the food still in their bill; if the disturbance persists, they will eat the prey themselves. Continuous disturbances, especially during the early breeding period, can cause breeding failures and the abandonment of breeding sites (405, 410, 632, 725, 159, 170, 162, 726). Humans caused the strongest disturbance at a Dutch breeding colony during the first weeks of June, although the flight distance was only 50 m, which is generally low compared to other breeding sites. At the end of July and particularly after hatching, the bee-eaters were less shy of people passing by (183).

Management

Conservation Measures and Habitat Management

The long-term protection of the species is undoubtedly connected with the protection of existing insect-rich habitats, and the creation of new insect-rich biotopes (727). In particular, the establishment of "insect-friendly" habitats in disturbed landscapes and the preservation of undeveloped landscapes around water bodies and coastal areas will be key for the long-term survival of European Bee-eater, especially in densely populated countries. Some steps that can be taken include creating edge habitat with abundant flowering plants around otherwise agricultural monocultures, which has already been demonstrated to increase bumblebee populations (728).

In addition to improving and protecting insect biodiversity, protection and maintenance of breeding sites is also crucial for bee-eater persistence. Long-term occupancy of breeding colonies can lead to "consumption" of the breeding wall if the density of burrows becomes too high; the bank wall can also become overgrown with shrubs or flattened by erosion (576). There are several measures available to restore banks used for breeding: 1) removal of shrubs and woody vegetation shading the bank, 2) digging out degraded walls to restore the bank wall; large, steep banks that have been occupied for decades need to be excavated to a depth of at least 2 m to remove all old burrows, and 3) removal of eroded material at the base of a steep bank can extend the colony persistence, and increase safety from ground predators (729). If the bank the old colony is built into is not deep enough to restore, new breeding walls can be created nearby, which are often colonized quickly (392, 730, 397). In Austria, existing valuable habitat in the vicinity of larger bee-eater colonies have been secured, and their development optimized by clearing dry grasslands and grazing them (731).

Ultimately, protecting European Bee-eater is a complex issue that requires many considerations. To preserve and optimize bee-eater habitat in abandoned lignite, loess, sand, gravel and clay pits, the following steps need to be considered (e. g. 392, 389, 732, 162, 386): 1) Close cooperation with all stakeholders must be sought, and quarry owners and local conservation authorities must be informed about the breeding sites; 2) steep walls in quarries must be excluded from any mining activities from the arrival of the birds until the young birds have fledged; 3) long-term existence of quarries depends on the maintenance and creation of new breeding walls, and plans must be developed early, whereby quarry owners must be involved in the concept development; and 4) to optimize habitat for bee-eaters, habitat for insects should also be preserved and created; these potential foraging habitats should be located at a maximum distance of 400 m from the colony.

Recommended Citation

Bastian, H.-V. and A. Bastian (2022). European Bee-eater (Merops apiaster), version 2.0. In Birds of the World (S. M. Billerman and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.eubeat1.02