-BANDING

A JOURNAL OF ORNITHOLOGICAL INVESTIGATION

VOL.VII JULY, 1936 No. 3

THE WHITE STORKAS A SUBJECTOF RESEARCHt

By ERNSTSCHI•Z Vogelwarteof Rossitten of the Kaiser Wilhelm Society for the Promotion of Science

THE White (Ciconiaciconia), as a strikingand confidingbird of largesize, is especiallyadapted for many linesof research. For a longtime the V.ogelwarte of Rossittenhas beenengaged in study- ing it, for this stationis situatedin that part of Germanythat is rfehestin , namely East P•. 1. DISTRIBUTION The numbers'of this beautiful bird vary greatly, as has been shownby the surveysmade in different placesin sincethe beginningof this century. Recently there has been an increasing number of observersin this field, and many countries have a con- siderable literature on their Stork populations. It is most im- portant that these surveys should be taken from a uniform point of view, and, if possible,in the sameyears, so that a comparisoncan be madeover as large a as possible. My project of an "International Population Survey in 1934" met with a cordial response,and hence we now possessfor that year a goodinsight into the Stork populationof all of Germany,Holland, Denmark, the Schonendistrict of Sweden,Switzerland, Austria, Czechoslovakia,parts of and , and also the Spanish Provinceof Avila. Omitting Latvia (the figuresfor whichhave not yet been reported), the total count comes to about forty-five thousandpairs. In Germany30,730 pairs with 64,772fledged young were recorded,of which more than half--16,602 pairs with 33, 751 young--belonged to , while western and southern Germanyis very poorin S{orks.In East Prussiaan averageof 44.5 pairs of Storksnest per one hundredsquare kilometers. Even more favorable is the Memel region just to the north--formerly a part of East Prussia--for here 69.1 pairs bred per one hundred squarekilometers. The highest concentrationis that reported by Count Wodzickifor the Rudki countyin the Wojewodschaft

•Translate.d from the German by Margaret Morse Nice. 99 100] Scn•5-z,The White Stork as a Subjectfor Research JulyBird-Banding

Lemberg(Lwow, Poland)with 105.8pairs per onehundred square kilometers. It is interestingto follow by meansof the figuresthe dependence of the Stork on environmentalconditions, especially food supply. The opportunities for nesting are also of great significance,and these are largely dependenton man. While in northwestern Ger- many the preferencefor thatchedroofs is striking (in Schleswig_ Holstein the ratio of thatched to tile roof was 87:3.5), in eastern Germany (East Prussiaand Silesia) the "tile roof is used as often as the thatched,but usually with the aid of an artificial support. Man must compensatewith this help for the lack of thatched roofs. Tree nestsare rare in many countries,but in others common,as in Upper Silesia (90 per cent) and in CheckishSilesia and Moravia (91 per cent). Here again man has an influence,for in the regions with nestson trees the inhabitants have the custom of placing the artificialsupport on treesrather than on roofs. Holland hasa large numberof pole nests(27.1 per cent), where the support is placedon isolatedhigh poles. •2. FLUCTL"ATIO_N-SI_N- •N*UMBERS The numbers of Storks vary much from year to year. We have nowreached a maximum which will probabl• not continue for long. Apparently there was a minimum about 1928, after which came a strikingincrease. Not everywhere,however: in Switzerlandwhich had about one hundred pairs at the beginningof the century, the populationdropped to 17 pairsby 1927, sincewhen it has continued to decreasewith 13, 10, 11, 11, 10, and 7 pairs in 1935, and several of theseraised no offspring. Saxony, which reacheda minimum in 1928 of only 13 pairs, quadrupledits population in a few years: 13, 15, 19, 22, 28, 37, and, in 1934, 54 breeding pairs! Two sorts of influencesmust be distinguished. The spread of civilization with its dangersfrom drainage, high-powerlines, etc., is injurious,especially along the bordersof the range. On the other hand, in the regionswhere Storks are commonand real competition occurs,it is chiefly the food supply and weather that are the decisive factors. In fact we seegreat differences in the reproduction-coefficient (numberof young fledgedper nest) accordingto the favorablehess of the year as well as of the situation. The averagenumber fledged in Thuringiain 1934 was3.6., but in the Memel region(with sandy soil) only 1.7. In East Prussiait was 2.7 in 1931, but in the drought year 1934, 2.0. The questionremains to be investigatedas to how far changesin the weatherof a periodicnature influencethe p0pu- lation. 3. FOOD The food of the Stork is of specialinterest to the hunter in thoso Vol. VII 1936 Scut'z, The White Stork as a Subjectfor Research [101

,4, TYPICAL STORE NEST IN E•sT PRUSSIA.

FiouR• 4 A VIEW OF THE EXPERIMENTAL STORKSOF THE VOOELWARTEOF ROSSlTTEN. 1021 ScuCz,The White Stork as a Subjectfor Research JulyBird-Banding, regions where this bird is common. Large number of stomach- analyseson the part of the Vogelwarteof Rossittengive little or no evidencefor the harmfulnessof the Stork, except in rare instances. On the other hand we have many proofs of the importance of this bird as wl•olesaledestroyer of mice (for instancein the great mouse plagueof 1930 and many other times) and of many kinds of insects. Beetles of all kinds and grasshoppersare devoured in numbers, as well as insignificant-lookinglarvae. A Stork had eaten more than sevenhundred larvae of saw-flies(Tenthredinidce) for one meal, while anotherhad the remainsof over seventyMay-beetles (Melolontha) in its stomach. On its winteringgrounds in the Stork is highly regardedas the "Locust Bird". 4. MIGR_(T•O.'•' The migration of the White Stork in Europe is peculiar,since the that nest east of the Weser River travel round the east end of the Mediterranean to reach eastern South Africa--a distance of over ten thousandkilometers--while the more westerlyStorks reach Africa by goingthrough southernSpain. It would seemthat some at least of these western Storks reach eastern Africa, for a dart found in a Stork killed in is believedby ethnologiststo have come from a Negro tribe inhabiting Kenya.. Yet we know for certain that someStorks occur in the west in tropical Africa. We are anxiously awaiting further recoveries. 5. NESTING The breedingbiology of this bird, particularly from the stand- point of behavior,is a fascina{ingsubject. In East Prussia the Stork arrives at the beginningof April, usually the male first and a few days later the female. As a rule an old nest is adopted, a set laid by the end of April and hatchedin thirty days. The youngstay somenine weeksin the nest and are typically altricial, during the t•rst weeks lying flat in the nest on the approach of a person, thus allowingthemselves to be easilyringed. Migration occursabout the middle of August, and in about seventy per cent of the casesthe young leave several days before their parents, the latter sometimes renewingcourtship activities at this time just beforetheir departure. The nestplays a very important role in the homelife of the Stork. Oneoften has the impressionthat it is first the nestthat is defended and secondthe mate. Very remarkableare the fights that regularly take place over nests that are already occupied. And even when excellentnests are presentin the vicinity ready for adoption! The fact of the occupationof a nestby a pair of Storksseems to present a challengeto strangersof the species,and it is a curiousfact that at times the intruders drive out the rightful owners, yet raise no brood themselves. In the reproductivemechanism of such indivi- duals,the instinct to possessa nest is present,but the rest of the Vol. VII 1936 SCHOZ,The White Stork as a Subject.forResearch [103

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F•u•m 2

A TRr• N•sr •N EAst PaUSS•A. pattern is lacking. These are probably two- or three-year-oldbirds that are not yet fully mature. 6. AG•. or Ba•.•.•nNG Year-old Storks never return to the home nest. They are often foundthroughout the summer in theirSouth African winter quarters. In two-year-oldbirds the mechanismof the reproductiveactivity is betterdeveloped, even if not fully so;they may at timeslay claim Bird-Bandh• 104] Sc•Cz,The White Stork as a Subjectfor Researc• zmr to nests,but do not breed. Three-y:earStorks often nest, but usually havefewer young than older birds, or perhapsn0n• at all. Four- year-oldStorks are •early always sexually mature. Thelarge troops of"Bachelor Storks" that roam around together in the breedingseason in East P•russiaand roostin treesat the edge of the woodsconsist to only a smallextent of year-oldbirds, but largely of two-year-oldor even older individuals. Perhapsthere are alsoold birds that fail to br6edbecause ofsome pathological reason. It wouldbe more correct tocall these troops of"Bachelors" or "Robber Storks" "Stork Children." 7. I•V•ORTALITY OF THE •OUNG The weatherappears to make little or no differencein the number of eggslaid, but often affectsthe number of youngraised through its influenceon the food s•pply. The smallestof the family (incu- bation alwaysbegins before the last egg is laid) is sometimesraised when'food is plentiful, but never when it is scarce. When the little bird lies feebly on the bottom of the nest, it is no longerfed. Older youngare thrown out, b•ut as I canprove by photographicevidence, smallyoung (for example,twelve days old and weighing570g.) are swallowedby the parent. Sometimesseveral small youngdisappear in this manner. If all the young die, there is a strongsuspicion that theyhave succumbed to a heavyinfestation of intestinaltrematodes, whoseintermediate host is a frog (Rana esculenta). 8. METHODS,OF INVESTIGATION The best method for investigating the life-history of this species is to concentrateon a small area, as here in Rossitten, and study the ringedbirds. We are trying to do what Mrs. Margaret Nice has done in her classical study of a small bird--Melospiza melodia. Naturally the technicalrequirements with a large bird which can 'hardly be ringedwhen adult are different--in somerespects easier, in othersmore diiticult. We can ring only the young Storks, and must plan the work with a view to the future, sincethe birds do not breed till several years old. For years the Storks of the Insterburg District in East Prussia havebeen systematically ringed. Especiallylarge rings with large figuresare usedso that they can be read with field-glasseswhile the birds are standingin normal fashionon the roof. In additionto the approximatelyfifteen hundred young Storksof this sampledistrict, the populationsof the Stolp District (Pommerania)and Kottbus (Mark )were ringed of late years,as well as the Storks of all Upper Silesia. Of coursesystematic observation must go hand• in hand with this work. The rings of the different regionshave• different numbers and are also easily distinguishableby the form• of the clasp. Vol.1936VII ScH•'z,TheWhite Stork asaSubject forResearch [105

F•Gur• 3 THE 1%L•aSOF THE VOGELWARTE OFI•OSSI'CrEN. AAA.Pelicans. AA. Swans, Golden Eagle. A. White-tailed Eagle,Bustard. B. Storks,•erons. BB. Special Rings for Researcheswith the WhiteStork. C. Medium-sizedRaptores. D. Crows,Medium-sized Gulls. E. Black-headedGulls,Lapwings. F. Starlings,Thrushes. S.Swifts, Kingfishers. G. Most Small Birds. BirdoBandin•. 106] ScuCz,The White Stork as a Subjectfor Research 5uly

9. HOMING EXPERIMENTS In the course of these studies, which are chiefly .concernedwith the instincts of this bird, the questionarises as to what external and internal factors are involved in the matter of way-finding in migra- tion. Our researcheshave been concernedwith the fall migration of the young birds. Several years ago 196 young Storks were confined and not releasedtill after the departure of the adult birds. With a few exceptions they found the right direction, apparently to a certainextent independentlyof' leadershipof experiencedindi- viduals. In 1933, 133 young Storks from East Prussiawere taken to west Germany and releasedin Essen (Rheinland) and Frankfurt (SIain), thus on the other side of the "migration boundary", on the 12th of September, at a time when the native Storks had already left. These visitors from East Prussiafor the most part took a southerly to southeasterlycourse that correspondedwith the direction from East prussia, but--wit. b_some exceptions--had nothing in common with the migration-route of the western Storks. It is noteworthy that young Storks from East Prussiathat were freed at an earlier, and hence normal, time in the west, for the most part migrated to the southwest and were found in certain cases with wild Storks that presumablywere acquaintedwith the route. So way-findingwith thesebirds seemsto dependpartly on a hypo- thetical inherited "instinct for direction" or somesimilar factor, and alsoleadership of moreexperienced birds, as well as to a smalldegree on the ecologyof the countrysidepassed over. I need not emphasize the fact that no real explanation is •ven by the term "instinct for direction" (Richtungstrieb). But we must attempt to penetrate more deeply into these problems.

10. SOME PRACTICAL ArrLIcATIONS Every scientistfeels the duty not only to orient his work from the theoreticalstandpoint, but alsoto make it serviceableto his country and fellow 'men. That these studies offer special responsibilities andopportunities to th• ornithologistis shown by the greatpublic interest in them, for they are concernedwith a bird that more than any other is closelybound up with life of the folk and that forms an integral part of the homeland. This is felt especiallykeenly in Germany. Hence the Vogelwarte of Rossittenconstantly receives questions as to his studiesand particularlyas to the possibilityof reintroducingthis well-loved bird in placeswhere it formerly nested.The researchesof Professor Thienemann have shown that it is possiblethrough raising young Storks in new, yet suitable localities, to establish them there, for vol. VII 1936 someof theseStorks returned in later yearsto breedin their adopted home. In this casethere was a distance of only one hundred kilo- metersbetween placesof birth. and adoption. Will transplanting over greater distances(one thousandkilometers) succeed? Follow- ing the great increasein the populationin East Prussiait was possiblein two yearsto sendover five hundredyoung Storks from East Prussiato west, middle, anti-southGermany. These birds were raisedin many placeson artificial nestsby peopleespecially suited to suchwork, and most of them migrated normally after about four weeks. Even if colonizingat this distance(and mostly on the other side of the migration boundary) is very doubtful, yet the raising of the birds, observations on them, and recoveries from a distance provideda great variety of interestingfacts. Best of all, we were able to share our abundanceof Storks in East Prussia and give many peoplethe great pleasureof seeingthe beautiful birds at close range and of watching their growth and flights. The studies on the White Stork would not have been possibleto the extent describedhad it not been for the help of the Vogelwarte and ornithologistsof all the countries in which Storks are found. For this fine coSperationI wish to expressmy gratitude.

REFERENCES UNDER TI-IE DIFFERENT YIEADINGS 1. E. Sc•Oz, Internationale Bestands-Aufnahmeam •VeissenStoreh 1934. Orn. 31'on.-Berlct•te,1936. No. 2:33-4L 2. F. I•-OR.XBERGER,Storchbestand des Ifreises Insterburg. Beitr•gezur Fort- pfianzungsbiologieder V•gel, 1936. No. 2:44-49. E. ScuCz,Der Bestanddes Weissen Storches'.in .0stpreussen 1931. VerhandL Ornith. Ges.Bayern, 20, 1933:191-225. 3. P. PUTZm,Neue Untersuchungen fiberdie Nahrung des •,Veissen Storches. DeutscheJagd, 1935. No. 14:256. 4. E. ScuOzund P/. W•.mO•,D,Atlas des Vogelzugsnach den Beringungsergeb- hissenan paliiarkfischenVSgeln. Berlin, 1931. E. ScuCz, Zwei neue Bei•r/ige zur Kenntnis des Afrikazugs der westlichen StSrche. Vogelzu•,6, 1935:125. 5. P/oRsTSmw•R% StSrche. Berlin, 1932. • VerlagReimer, with 80 pla•es. 4.80 RM. E. ScuCz,•'ber biologle und 0kologie des Weissen S•orches. Proc. V/IIth Intern. Congress,Oxford (in press). 6. J. Sxmr•;B•crmRe E. ScuCz,I1 problemadelia maturit{ sessualenella Cicogna bianca. t•assegnaFaunistica, 2, 1935:3-23. 7. E. ScuCz,Beobachtungen an beringtenStSrchen zur Brutzeit. Beitrdgezur Fortpfianzungsbiologieder Vsgeh 1935:61-68. L. SZ•D•%Warurn wirft der S•orchseine Jungert aus dem Nest? Journ.f. Ornith. 83, 1935:76-87. 8. E. ScsCz,XXVIII. Bericht der VogelwarteRossittem Vogelzug,6, 1935: 53-66. 9. E. ScuCz,Vom S•orchversuch1933 der VogelwarteRossitten. Vogelzu•,5, 134:21-25; reviewed in Bird-Banding, 1934:95. 10. E. ScuOz,0stpreussische Jungst6rche als G'aste in FremdenGauen. Ausder Heimat, 1936. No. 2:43-50.