POTGW - Pick of the German Week 12/2000

PICK OF THE GERMAN WEEK 2000

Pick of the German Week 12/2000........Short-haul Storks.......Survival of the fittest - Roe Deer......Neighbours in the Nest.....

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The Red Kite Milvus milvus
German Bird of the Year 2000

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PICK OF THE GERMAN WEEK 12/2000

News from the GermanBirdNet
and other sources...

BIRD(S) OF THE WEEK

After a stutter and a cold snap the wader migration takes form – Sociable Plover (Chettusia gregaria) in Bavaria – Black Grouse (Tetrao tetrix) display at a lek on the Saxon-Czech border, but numbers down on last year – Pipits and Wagtails (Motacillidae)in increasing numbers – Ospreys (Pandion haliaetus) and Storks (Ciconia ciconia & nigra) back on their nests – Swallows and comrades (Hirundinidae) moving further north.

NEWS OF THE WEEK - CONTENTS SUMMARY

1. Upstairs, Downstairs – Shared Nest Boxes
2. Short-haul Storks – not a welcome development?
3. The Roe Deer in Germany – Survival Expert

UPSTAIRS, DOWNSTAIRS - OR FRONT AND REAR?

The question in GermanBirdNet:
"Has anyone experience of co-habitation (breeding) in nestboxes by Barn Owl (Tyto alba) and Kestrel (Falco tinnunculus)? Are there particular specifications? Do the birds breed at the same time or one after the other?"

An answer from Peter Finke:
"I don't know of any laid-down specifications for this type of occupation. In the local area here, among the hundreds of broods – including controlled or ringed broods – kestrels are frequently found nesting in barn owl boxes, including mine at home. The kestrel usually breeds in the entrance, not in the actual box itself, which is separated by a partition. There are however cases where they move in completely! Almost every year there are isolated reports of kestrels laying in the entrance area and barn owls in the rear of such nest boxes. Sometimes the brood takes place concurrently so that the owl has to step over the 'sleeping' kestrel during the night, while the daylight activity of the falcon disturbs the owl. Sadly, in my personal experience, such broods are invariably unsuccessful. I don't however exclude a successful 'co-brood' if the box is roomy enough. The normal boxes (100 x 50 x 50 cm or even smaller) are simply too small although, as we see, they are successfully occupied. A young barn owl family is often numerous and so active (practice 'mouse-jumps', running and fluttering around) that a nest box at least twice the size would be much better. Perhaps the tenant and their lodgers would then get on better with one another. But that's outside my experience."
Peter Finke Bielefeld University

SHORT-HAUL STORKS – NOT A WELCOME DEVELOPMENT?

Timing is of the essence for north European White Storks (Ciconia ciconia) when returning to their nesting areas in Spring. Their punctual arrival between the start and middle of April, after a 6,000 – 8,000 kilometre trip from Africa, is essential to breeding success. The emergence of the young storks after a 32 day incubation period must coincide with a good supply of fat and juicy worms. In late spring, the moist soil in our latitudes is ideal for a stork-friendly diet. But arriving at the right time is no help if your patch has been usurped by an even earlier competitor.

The story of the 'short-haul' storks started just after WW II in Switzerland, where feeding stations were set up to encourage a return of the lost stork population. It was discontinued after well-founded fears by biologists that the birds become dependent on this source of nourishment and can no longer cope for themselves in the wild. Some storks have found an elegant alternative. By overwintering in zoos and wildlife parks in central Europe (the sun-lovers) settle for rubbish tips in Spain), they avoided a tiring and dangerous trip and had more than a head start in the choice of nest site for their brood. Proof of this behaviour has been gathered by information on rings (read and report those rings birders) and more recently by the fitting of transmitters which send signals to orbiting satellites.

A stork notorious for jumping the gun, No. 981 B, born in a breeding station in Wiesbaden, has been the front runner in Brandenburg for three years in succession. And he not only captures the best nest site on a barn roof; he is an attraction for the local media. One cannot accuse him of not making the most of his advantage. Last year he and his partner raised 5 healthy young, one of which was sadly lost to overhead electricity cables. The others did not take after dad; they all headed to Africa for the winter.

Although the world population of the White Stork is increasing at a satisfactory rate; totals of 166,000 pairs were estimated in 1994 (1,300 in Brandenburg – almost a third of the German population), the stork is still regarded as a threatened species and measures to protect them on their migration routes and in the transit areas are being actively pursued by national and international organisations.

THE OCCASIONAL NON-AVIAN ARTICLE
THE ROE DEER – SURVIVAL EXPERT 'PAR EXCELLENCE'

There are an estimated 5 million roe deer (Capreolus capreolus) in Germany of which 1.2 million are shot each year. In the European animal kingdom the roe deer's natural enemies are the wolf (Canis lupus) and the lynx (Lynx lynx), both still rare in Germany; with the fox (Vulpes vulpes) ready to include a baby fawn in its diet given half a chance. Despite the heavy depredations by man and his weapons, the rifle and the motor vehicle, the deer proves the theory of the survival through fitness – and adaptation.

The success story of the roe deer, in a habitat stretching from the Iberian peninsula to Siberia, goes back more than 10 million years. It survived even the bitter cold of the Ice Age where most of the other European fauna was forced out by more hardy races.

One of the principal reasons for its survival is its well-organized reproduction strategy. Whereas the larger red deer (Cervus elaphus) and fallow deer (Dama dama) usually have their mating season in Autumn; the roe deer mate in high summer. Their sexual activity increases with the length of the day with an willingness to mate linked directly to the strength of the sun and the length of daylight hours. The availability of food is also at its greatest at this time . Although the length of pregnancy is five months, which would lead to the fawns being born in the depths of winter, the doe keeps the fertilized egg in a state of suspension for several months. The birth then takes place in May when both the climate and fresh food supply are optimal. In addition the fawn, with its dappled coat, is well-camouflaged in the sunny springtime forests and, like the mother doe, emanates no scent. The crafty fox must literally trip over his prey to earn a good meal.

True to their finely-honed survival skills, the roe deer's feeding cycle and diet is carefully balanced. The animals graze every 2 to 4 hours to keep their energy levels topped up. Their digestive system adapts to the available environment. In summer the deer eat food rich in protein – herbs, buds and fruits of the plants and trees. In winter their stomachs adjust to a high fibre diet. Unlike many animals they remain in their familiar territory in the colder months and drastically reduce their energy output. They also grow a thick winter coat, which is gradually shed in the spring making them look somewhat moth-eaten.

In the south of Berlin, scientists from the Karlshorst Institute for Zoo and Wild Animal Research have fitted 4 roe deer with radio transmitters in order to gain more information on the animal and its habits. Although it is well know that they are active mostly at dawn and dusk, the transmitters will enable more detailed information on their movement and feeding habits to be collected. The devices record the territorial changes in summer forced by the exodus of the city-dwellers into the forests; and of course in the hunting season from June to February.

According to a project member, the German roe deer population has been 'over-protected' for centuries; a situation exacerbated by the decline and/or extinction of its natural enemies. Others would say that man has as usual gravely upset the natural balance. Even the reintroduction of, or resettlement by lynx and wolf would have little effect. The other natural competitors for food sources, the European bison (Bison bonasus) or the Elk (Alces alces), not to mention the wild horse (Equus ssp.), have also been exterminated or pushed into marginal habitats (now entitled 'reserves') by mankind.

The modern foresters, still traditionally committed to nature but whose livelihood and career more and more depend on economical management of their commercial assets, are faced with a conflict of interest. As soon as spring arrives the deer find the young shoots irresistible. Without human intervention – fencing off or shooting – the forest itself is threatened. The spread of new undergrowth is inhibited and the saplings which should replace older trees are a gourmet course on the menu of the roe deer. Increased fencing off brings its own problems. The deer are forced to seek other food sources. According to 'The Atlas of European Mammals'*: "a new ecotype of field roe deer lives in open agricultural areas." In Spain some roe deer have now switched their diet entirely long-stemmed maize. The answer for some is more culling; for others providing feeding stations for the deer, which leads to semi-domestication.

Statistics* Population density 10-20 individuals/100 hectare in favourable habitats – even higher in suburban environments. Other approximate European annual hunting bags: Netherlands – 10,000 Norway – 50,000 – 60,000 Sweden – 300,000 Hungary – 40,000 Czech Republic – 115,000 Switzerland – 50,000

*The Atlas of European Mammals, A J Mitchell-Jones et. al, published by T & AD Poyser – available through:
Amazon Internet Bookstore

David Conlin
GermanBirdNet Berlin

The contents of POTGW are © David Conlin 2000 unless otherwise stated and should not be copied in whole or in part, or otherwise publicly reproduced, without his consent.

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