Like every year, there are tens of different species of birds that come back from Africa at the end of their wintering season to breed in Europe. From the giant griffon vultures, to the tiny willow warblers, thousands of them fly every day over our forests, countryside and cities. The vast majority of them go unnoticed to most of us, but one of these species stand up among all the others for making their annual passing more than evident, the European bee-eater.
Every day from late March or early April, they pass overhead at low altitude in groups of about 25 to 30; rarely they are seen traveling alone. They are normally heard before you see them. The distinctive fluted song never goes unnoticed by those who know it. Unlike most migrating species, bee-eaters are noticed because they travel in large groups, which can be heard before being seen. His unmistakable song never slip past by those who know it and encourages us to look up to the sky every time we hear them. You can listen to it here.
Apparently adults move south first and later the flocks are mostly composed by young individuals that are bundled already in the breeding areas. In the young the two central tail rectrices do not protrude as much as in the adults, their plumage is more greenish , and the red of the eyes is duller. The vast majority of bee-eaters that pass through the Straits of Gibraltar are Spanish birds, those from the colonies in southern France pass over more eastern areas of the Mediterranean Sea.
The bee-eater is certainly one of the most colorful birds in our latitudes and nature photographers and birders enjoy them every year. It is very common to see them perched on power lines while passing along our roads and dirt tracks, giving us a huge explosion of color and lively vitality. With a pair of binoculars you can have a good time watching their elegant comings and goings for insects. Furthermore you can stop and try to tell apart males from females. No easy task nor obvious, but with a bit of visual acuity and looking from below you will see the brighter blue of the male breast and their wing large coverts (wing area closest to the head) more brown reddish than that of the female. Male to the right on the photo.
It is well known their ability – as specified in its name – to hunt bees, bumblebees and wasps. Before eating them, they remove the stinger carefully by striking them repeatedly on the branch where they are perched. This skill is not supported by any special physical resistance to the bites, beyond having a special designed peak which keeps the eyes away from the dangerous poison. Unlike what its name suggests they do not only feed on bees, but all kinds of insects. Around 70% of Spanish bee-eaters diet is composed by honey bees although the impact on the local population of bees is very small since the eat only about 1% of worker bees.
They breed in colonies and their nests are located at the end of a tunnel excavated in sandy slopes of about 75 cm in length, but may reach up to 1.5 meters long. Each pair need to extracts about 10 to 15 kg of sand to build a nest. At the end of this arduous task, they chipped up to 1.5 cm off their beaks, sometimes not regularly, with the top or the low part of the peak more worn. Bee-eaters require around 225 bees a day when they are raising their young. Clutch size is 6 – 7 eggs.
This is one of the few birds that perform breeding in cooperation. This means that other individuals who are not the parents help to feed the chicks, circumstance that promotes healthy and numerous clutches. In our area, in addition to the bee-eater, only moorhen, long-tailed tit and dunnock show this cooperative behavior. Genetic studies have shown that these ‘helpers’ are invariably the brothers and sisters of the birds being fed, usually the offspring from a previous brood. If nest sites are limited by the size of the sandbank, then helping their siblings to survive is the most useful thing that young bee-eaters can do until they can claim a nest-site of their own.
Nesting season is time for family alliances and intrigue. Parents with helpers can provide more food for chicks to continue the family line. The trick, of course, is to recruit helpers, they often use strong-arm tactics. After digging the burrow, a male bee-eater typically engages in courtship feeding, impressing his mate by bringing her a tasty bee or dragonfly. Parents have been reported to butt into their son’s business, begging for the courtship treat or barging in between the mated pair. If that didn’t work, a parent might block the entrance to the son’s burrow, preventing the female from entering to lay her eggs. After a while some sons succumbed to the pressure, abandoning their own breeding efforts to become helpers at their parents’ nests.
They’re more likely to find helpers among males whose own nests fail through natural causes. Trickery and theft aren’t uncommon, though. Almost everything naughty you can think of happens in those colonies. If a female leaves her burrow to feed, another female may sneak in to lay eggs, a tactic to fool the neighbor into raising a stranger’s brood. Similarly, if a male leaves the nest unguarded, other males may seize the opportunity to copulate with his mate. Other bee-eaters occasionally turn to robbery, harassing neighbors who return with food until they drop the insect and the thief can fly away with the goods.
Once the birds arrive in Africa, the social season kicks into high gear. Male bee-eaters stick with their own clan, while females leave to add their genes to a distant pool. Grass fires sometimes function as mixers, drawing bee-eaters from miles around to feast on the fleeing insects. Spanish-born males meet Italian-born females, Hungarian birds meet Kazakhs, and mates pair up for life. Around April, they are back in Europe, one year old males return to their natal grounds with their foreign mates.
It’s a short, spectacular life. A long-lived European bee-eater will survive five years, maybe six. The rigors of migration, dodging falcons along the way, take a toll on every bird. Bee-eaters today also have to contend with the loss of insects to pesticides and the disappearance of breeding sites as rivers are turned into concrete-walled canals. But what a story: bee chases, hive raids, brush fires, nest intrigue, and Gibraltar crossings packed into those few years.
They are definitely a priceless gift of nature that come every year to brighten our skies and our lives.