Bird Migration

BIRD MIGRATION.

Palestine as major migration route.

Although not mentioned by name, bird migration is implied in several Biblical passages. This is not surprising, for in spring it is an obvious natural phenomenon of the whole region. Jeremiah 8:7 is the clearest reference, “Even the stork in the heavens knows her times; and the turtledove, swallow and crane keep the time of their coming.” All these are birds of passage, though the precise identity of crane and swallow may be argued. The migratory habit of the quail made it of great importance to the Israelites, for this edible bird flew NE across their exodus route on its spring passage (Exod 16:13ff.). Palestine’s position, running more or less N and S at the E end of the Mediterranean, makes it a main route for migrants passing between E and Central Africa, where they winter, and a great area of Central and E Europe and W Asia, where they nest. Birds wintering in W Africa normally cross into Europe at Gibraltar. Along the N African coast are five or six regular take-off areas, but the greatest single concentration flies N down the broad, fertile Nile Valley, from which the most natural route is over Pal. A more direct line to Turkey, even via Cyprus, involves a minimum sea crossing of 300 m.; a more easterly course takes birds over the extensive deserts of Jordan and Syria, with a stretch of at least 500 m. where there may be oases but little available water at most seasons. The long belt of country between the Jordan Valley and the coast offers several advantages, esp. in spring when much of the land is still green. For many species the return migration in autumn follows a somewhat different pattern, the birds being spread out over a broader front, largely because of the prevailing winds, while their departure from their breeding grounds may take place over a period, the adults of some species leaving perhaps weeks before the young birds.

Advantages of coastal route.

For large birds this route lets them ride the thermals which are a feature of the desert and the Rift Valley. For great numbers of smaller birds it offers both food and water at fairly frequent intervals. The recent spread of cultivation, often irrigated, has much increased the facilities available to the birds, esp. in the Negev. On the Israeli side of the passage route, where irrigation is most widespread, these small birds and most larger ones pass unmolested, whereas in most adjoining countries many of the small birds are trapped for food.

Many birds are found among the migratory species.

While the c. 350 species cannot all be put into precise categories, for many would come into more than one, these birds may be called resident, summer breeder, winter visitor or passing migrant. Less than seventy are classed as resident, so some eighty percent are migratory in greater or lesser degree; since these latter include some of the more numerous kinds the proportion of resident individuals is even less. About fifty are birds that breed farther N, some inside the Arctic Circle, and winter in Pal. Some members of these species fly right through before stopping off and so are also passage migrants, which comprise the biggest class—at least 130. For these Pal. is merely a country on their route. More than thirty are listed as stragglers, mostly migrants that normally use other flight lines and are seen in Pal. only when blown off course. The remaining, c. fifty, the summer breeders, have wintered to the S and for them Pal. is a breeding ground. In the past 2,000 years there have been widespread changes in flora and fauna, but the large mammals have been most affected. (See Fauna.) Since the early 1950s the status of certain resident birds has changed, most for better and some for worse, but for migratory birds this tract has long been a major route, and there is no reason to suggest that the pattern observed today is basically different from what it was in the days of the Lord and for many centuries before that. Jeremiah’s list included small, medium and large birds of different families. He did, in fact, quote a true sample, for almost every family found in this area includes some migrants.

Low-flying migrants.

It is hard to be in Pal. during March and April without quickly being conscious of the passage of birds, esp. along the roads, where telegraph lines, electricity supply cables and trees make convenient resting places. Brilliantly colored European rollers, bee-eaters, and turtle doves are perhaps the most evident, and this is the season when “the voice of the turtledove is heard in our land” Song of Solomon. Every oasis in the desert is alive with birds, esp. small members of the Passerine family, the perching birds. Warblers are found mostly on the bushes and crops, searching for aphids and other insects; commonest are lesser whitethroat and blackcap. At least four races of yellow wagtail, each using different nesting areas in Europe and Asia, are busy hunting on the ground, together with red-throated pipits which are more or less midway between their winter home in Africa and nesting sites in Lapland, within the Arctic circle. The pattern may be different in other sections of their route, but at this point these birds mostly move N in a series of short stages, drinking and feeding as they go.

High-flying migrants.

The casual visitor is less certain of seeing the large migrants. They come through less regularly, traveling in longer hops and being more dependent on weather conditions. A cloudy spell, with some rain, may occur even in March and April, esp. in the northern part of the Rift Valley, and this interrupts the formation of thermals on which these birds depend. The use made of thermals is most easily seen over the desert. In spring the night temperature drops and it may be well into the morning before an area heats up enough to start a column of warm air rising. Meanwhile large birds of prey—kites, buzzards and eagles—cruise around in a rather haphazard way trying to get started, but soon give up and search elsewhere if the life is not enough. When a real thermal starts its presence is quickly seen; birds stream toward it and as soon as they enter the column of rising air they set their wings for maximum climb and spiral up to perhaps 6 or 7,000 ft. before gliding N, losing just enough height to maintain speed. With a favorable wind they travel many m. with hardly a wing beat before having to find a further thermal.

Travel pattern of large migrants.

The more precise pattern depends on the food habits of the various families, but this type of movement (gliding) involves little effort and therefore minimum use of food reserves. Large migrants through Pal. include three main groups.

Birds of prey.

Being flesh-eaters they go for long periods without food and prob. take little on some stretches. However, some have suffered severely from eating poisoned corpses esp. in the Jordan Valley. See nodetitle 3 F (5).

Pelicans.

These are specialized water birds returning from the lakes of Central Africa, esp. Uganda, and in earlier times their main, perhaps their only stopping places were the swamps, in particular the Huleh Lake through which the Jordan flowed. This has now been drained, as well as the coastal marshes, and wide areas of fertile arable land, flanked by complexes of fishponds, take its place. A lake of some 400 acres, part of a nature reserve, is now the only open water suitable for pelicans (which seldom seem to use the Lake of Galilee) and if a break in the fine weather occurs when they reach this point they must sit it out in safety either on the small lake or in the center of one of the vast arable fields. At this season the ponds are carefully guarded, for a flock of 400 pelicans could take over one ton of edible fish daily.

Storks.

Both black and white storks pass through Pal., taking different routes for most of the way. The former is scarce and travels in small numbers; the latter goes N in flocks of many hundreds, affording most spectacular sights, and it is likely Jeremiah drew his hearers’ attention to such a flock as he told them that “Even the stork in the heavens knows her times” (Jer 8:7). Storks eat small animals, ranging from snakes, frogs and mice to worms and grasshoppers; they feed regularly when on migration and today the large flocks mostly find space and food in safety in the upper Jordan Valley, but from Feb. to early May white storks may be seen in greater or lesser numbers following the plow, drawn by either tractor or beast of burden, in many parts of Pal. In autumn the wind pattern makes it easier to take a course farther inland and the stork migration is less conspicuous. More details about these birds are given in their individual articles, while many other Biblical species are to some extent migratory. It is not surprising that few of the smaller birds of passage find mention, for even today these are virtually unrecognized and unnamed by the ordinary countryman, but there is little doubt that these birds have been passing this way since long before Abraham’s time. See nodetitle.

Bibliography

B. Berg, Mit den Zugvogeln nach Afrika (1933); Peterson, Mountford and Hollom, Field Guide to Birds of Britain and Europe (1954); (This covers almost every bird that the ordinary visitor to Pal. is likely to see.); D. Harrison, Footsteps in the Sand (1959); R. E. Moreau, “Problems of Mediterranean-Saharan migration,” Ibis, 103a. 373-427, 580-623; P. Arnold, Birds of Israel (1962).