The Bee-Eaters

C. Hilary Fry

• Publisher: T & AD Poyser
• Year: 2010
• Print ISBN: 9781408136867
• eBook ISBN: 9781408136874
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Zoology
• Index: Biological Sciences

Dr Hilary Fry's study of the bee-eaters covers all 24 species of this colourful Family, which ranges from southern Europe, Africa and the Middle East to India, China, south-east Asia and Australia.

A major part of the book comprises the species accounts, with complementary colour plates of 42 species and sub-species and detailed maps depicting the geography of their evolution. In addition there are chapters on the bee-eaters' evolutionary development, their food and foraging behaviour, and relationships with apiculture; of particular interest are chapters on social and reproductive life, the role of 'helpers' at the nest, and the meaning of plumage and social distinctions between the species.

The author's colour plates delight the eye and accurately portray plumage and 'jizz'. They are fully supplemented by more than 100 drawings by John Busby, capturing the essence of these birds with a rare deftness and vitality.

1: Introduction

According to my reckoning there are 24 species of bee-eaters, falling into three genera with an essentially tropical distribution in the Old World, and the taxa* which I recognize are set out in the list later in this chapter. Eleven species are monotypic and seven others have only two subspecies (races) each. Of the remainder easily the most variable geographically is the Little Green Bee-eater Merops orientalis—its populations differ amongst themselves quite sharply in head colours and tail-streamer lengths, but by and large the polytypic bee-eaters each exhibit little plumage variation. In total I admit 52 taxa, the species and most of the subspecies being readily separable and only a few races needing critical examination in the museum for their determination. All the world’s bee-eaters are portrayed in the eight colour plates except ten poorly differentiated races—42 kinds altogether.

In a distinctive and rather close-knit family of animals showing only a small amount of subspecific variability, one would expect to find correspondingly little distinction between the species themselves. A glance at the Plates will show that in the Family Meropidae, however, several kinds are highly distinctive in appearance. Most are grass-green above, buff or pale blue-green below with bright, contrasting throats, a black mask, dark gorget, black trailing edge to the wing, and rufescent green tails with long streamers; but none of those characters is universal. The most obvious departures are the Red-bearded Bee-eater Nyctyornis amicta with its bilious plumage together with the other rainforest forms shown in Plates 1 and 2, and the shocking-pink birds in Plate 8. The low intra-specific and high inter-specific variation means either that bee-eaters do not differentiate readily or (contradictory as it may sound) that they are differentiating so rapidly that in no evolutionary time at all their races have become good, distinctive-looking species. In fact it is my belief that some bee-eater lineages have ‘stuck’ but that others are evolving fast (Chapter 3).

* For the non-biologist there is a glossary of technical terms in Appendix 1.

In the field bee-eaters—at least most kinds of Merops—come over as alert and vivacious birds: it is one of their more appealing characteristics. True to their name, they do indeed feed mainly on bees and related Hymenoptera. Such insects fly fast or are manoeuvrable, or both, which dictates that their avian predators shall prey on them in open situations—it follows that bee-eaters are conspicuous birds, perching in the open and often darting out after a passing insect. They spend the greater part of the day hunting, and their eminent watchability is enhanced by their generally permitting close approach. Carmine Bee-eaters M. nubicus frequently forage not from a perch but high in the sky, sailing around on the acute triangles of their wings in a leisurely-looking way and, with a few quick beats, effortlessly twisting after an insect. A few other large bee-eaters hunt likewise, and even the smallest ones, flycatching from their look-out perches, have the same enviable mastery of flight (although by no means are their sallies always successful). Continuous small postural movements show that a perched bee-eater, when not engaged in preening or interacting with others of its kind, is ever searching for food: looking to right and left, cocking an eye to the sky, following with turning head the flight of an insect at grass level, or starting forward with quarter-opened wings (an ‘intention movement’) before deciding better of it.

Those lucky enough to have watched birds in Africa or to have encountered bee-eaters in Europe, Asia or Australasia will know that these attractive birds are lively not only in pursuit of prey but also in interactions with others of their species. In even the least gregarious sort, singletons are rarely found and occurrence in pairs or family parties is the rule. A bird keeps close company with its fellows; they habitually perch close, even huddled up against each other, and pursue the same activity all together, wheeling round, preening, feeding or bathing. In the execution of commonplace daily activities they seem to show a degree of mutualism, as if seeking security in numbers and comfort in the reciprocation of behaviour.

Although without any great variety of expression they are quite vocal, the common voices being contact-calls pleasing to the human ear, rolling pruuik-pruuik’s and the like. High-flying flocks of migrants and the hubbub of a large nesting colony can be heard a kilometre away. At colonies much of the noise is of greeting and strident bickering, yet for all their rivalries and aerial chases they never inflict any physical damage upon one another, and in fact a much more evident feature of bee-eater society is the tenacity of individual bonds, A notable characteristic of many species, and one that has been the principal target of recent researches on the Meropidae, is the co-operation at the nest between the parents and one or several helpers, which undoubtedly ameliorates the often precarious lot of the nestlings.

A large number of birds, as well as a few mammals, are known to eat social bees and wasps from time to time, not only the stingless males or drones but also the stinging and often highly dangerous sterile females or workers; to justify the risks involved—risks if the predator knows the danger—the rewards are probably high with the bee or wasp a money-for-jam meal. In warm climates ants, wasps, bees and such like hymenopterans, many venomous, are abundant and they form a high proportion of daytime-flying insects. But surprisingly few birds have evolved in any sense as professional bee and wasp predators, and paramount amongst them are the bee-eaters of the Old World tropics and, in the New, the unrelated but extraordinarily convergent jacamars (Galbulidae). Whether the last have any obvious ways of devenoming bees is not known; but bee-eaters certainly have. Except for Carmines, which sometimes evidently de-sting bees without breaking flight, bee-eaters always return with a captured bee to their perch. There they deftly juggle it until it is held crosswise at the tip of the mandibles, near the end of the abdomen. Bouts of hitting the head end of the insect to one side of the perch alternate with rapid rubs of the tail with its sting to the other, like somebody vigorously using an india-rubber. I call it bee-rubbing and it is peculiar to the treatment of stinging Hymenoptera.

Even at distance it is easy to see if bee-rubbing is included in the immobilization treatment of an insect and, in the field, that provides a ready means for reckoning the proportions of Hymenoptera (or strictly of stingers) in a bird’s diet. Close at hand a smooth perch can sometimes be seen to be wetted because rubbing causes the bee or wasp to discharge its bowel-fluid and poison; at times the sting is torn out and sticks into the perch, although more often a bee is swallowed with its sting still intact.

For the researcher studying their food biology a further convenient habit of bee-eaters is that several times a day they regurgitate a neat, black, odourless pellet of the indigestible remains of their prey. The fresh pellet is compact, 1–3 cm long, and easy to find below favoured perches. On stubbly or broken ground I have gone so far as to pin down sheets from which the day’s harvest of pellets can be collected in a few seconds; but under roosts and near nests a mass of pellets can generally be obtained whatever the terrain. They can readily be dissected and analyzed, rendering it quite unnecessary to subject bee-eaters to the more brutal techniques like the use of emetics, sometimes applied to other birds.

All bee-eaters nest in earth holes. They excavate new holes each season or much less commonly they use a previous year’s nest. Excavating, done with the beak and feet, is a powerful compulsion; it seems that both sexes need to perform a certain minimum of digging before they can successfully enter into the next phase of reproduction. In the immediate environs of the definitive nest-hole two or three ‘false starts’ are usually to be found, incomplete tunnels anything from a few centimetres long to almost full length, which are not so much diggings which failed when an obstruction was encountered, or soil of the wrong consistency, as the evident dissipation of a behavioural drive. In some instances false starts seem to be the product mainly of supernumeraries or helpers at the nest. Colonial bee-eaters have their nesting cliffs riddled with holes, but fewer birds comprise the colony than might be supposed, since maybe half of the holes are false starts or otherwise abandoned.

It is not difficult to locate bee-eater nests, solitary or aggregated. The birds make little effort to conceal their visits, which are particularly frequent and obvious after the eggs have hatched. Some bee-eaters prefer to use cliffs, generally between one and five metres in height, often but by no means always by water, others may use sloping or flat ground. In Africa, Red-throated Bee-eaters M. bullocki and White-fronted M. bullockoides nest only in cliffs, digging nearer to its top than its foot, so that in high cliffs the nest entrances are as difficult of access for the investigator as those of some cliff-nesting seabirds. Little Bee-eaters M. pusillus use low cliffs of a metre high or less, and sometimes a hoed ridge in a pepper-field or even a dried-out hoof depression will suffice for tunnelling to begin. Interestingly this bird will also use a very specialized site: the sloping roof of Aardvark burrows, with the nest-hole entrance a half-metre or more into the cavernous mouth of this large mammal’s lair. Of all species the Rosy Bee-eater M. malimbicus makes the closest approach to being exclusively a flat-ground nester. It breeds in spectacular colonies of tens of thousands on sand-bars in the great West African rivers; only four or five such colonies have ever been discovered, yet the birds can be so abundant that from 10 km away it needs only a morning and a little luck to home onto the nesting site.

In some migratory forms, pair-bonding and helper-bonding occur before the prenuptial migration, in others after. Excepting that splendid sub-Saharan bird the White-throated Bee-eater M. albicollis, courtship does not amount to anything much, but greeting ceremonies (the same as in the initial courtship) continue throughout the nesting season. After tunnelling finishes and little mounds of fine soil have grown in front of the nest entrance the pair, with helpers if they have any, start roosting in the egg chamber, a low-ceilinged oval expansion at the end of the 1–3 m long tunnel. European Bee-eaters M. apiaster winter in Africa and on their return, after digging the nest, they lose no time in laying eggs at 1–2 day intervals until the clutch is complete in about six days. Red-throated Bee-eaters in the savannas of West Africa, sedentary birds, encounter an unusual difficulty: toward the end of the long dry season when they lay, the ground has dried to a concrete hardness. They obviate the problem simply by excavating their nest holes some four months in advance when, at the end of the previous wet season, the earth is moist and workable. (We need not credit them with foresight and intelligent problem-solving; the operation of natural selection will account for their behaviour.)

In all species incubation starts at the time the first or second egg is laid, so that hatching—after some 20 days—is sequential too. As in most cavity-nesting birds the eggs are subspherical and immaculate white, and they have a delicate pink translucence when new-laid. There is no nest material as such, but some protection from breaking against the hard earthen floor is afforded to ...

Table of contents

• Cover
• Copyright page
• Contents
• Dedication
• Preface
• Acknowledgements
• 1: Introduction
• 2: Species accounts
• 3: The origin of species
• 4: Food and foraging
• 5: Bee-eaters and apiculture
• 6: Social and reproductive life
• 7: Evolving specific differences
• Appendix 1: Glossary of evolutionary and other terms
• References
• Colour Plates