Peregrine Falcon populations

Peregrine Falcons and their recovery

by Ian Newton

The Peregrine Falcon has long fascinated mankind, in earlier centuries mainly through its role as the ultimate falconry bird, and more recently because of its position as a cause célèbre in international conservation. I have often thought that people who work with Peregrines are themselves rather special, partly because researching wild falcons can be physically demanding, and partly because of the enormous charisma of the bird itself, and the spell it seems to cast on all who get to know it. Many a lifetime has been spent in obsessive awe of this special species. Some of current enthusiasts are professional biologists, but most are dedicated amateurs who are motivated by their love of the bird, and the spectacular landscapes in which it often occurs.

The recent ground-swell of interest in the species dates from the 1950’s when Peregrine populations over much of the developed world were plunged into rapid decline, following the widespread introduction in agriculture of the organo-chlorine pesticides. These chemicals included the infamous DDT, which was soon found to account for the shell-thinning and egg-breakage which had become a feature of all declining Peregrine populations. They also included the highly toxic cyclodienes – aldrin, dieldrin and others – which poisoned many Peregrines, contributing to population collapse. These chemicals are fat-soluble, so accumulated at sub-lethal level in the bodies of many bird species. The Peregrine, feeding on other birds, obtained a cumulative dose. Many bird and other animal species suffered population declines during the organo-chlorine era, but the Peregrine and other bird-eating raptors were some of the most seriously affected, disappearing altogether from large parts of their historic range. Cliff after cliff, forest after forest, which formerly rang to the defiant calls of Peregrines, became silent and abandoned.

Because of their obvious effects on wildlife, and suspected effects on people, the organo-chlorines were gradually phased out of agricultural use, especially as alternative chemicals became available. The last 40 years, therefore, have seen a progressive recovery of the Peregrine, and its re-establishment in former haunts. In many areas the process of recovery has been assisted by reintroduction programmes carried out by dedicated individuals. Many studies over this period have documented this recovery, including some described in this volume. In many regions, Peregrine numbers seem higher now than in pre-pesticide days and birds are nesting on city buildings on a scale previously unimagined. However, one former population which is still not fully re-established is the tree-nesting population which once bred over the mid latitude lowlands extending from Germany into Russia. Good progress has been made on the re-establishment of tree-nesters in Germany, but further work is needed elsewhere, and it is gratifying that a start has been made in Poland.

This book represents another significant milestone in the history of Peregrine studies, adding to our knowledge of the species and its recovery. It results from a conference held near Poznan in Poland in September 2007, attended by some 60 Peregrine enthusiasts, drawn mainly from Europe, but also from North America, Australia and South Africa. About 50 participants presented papers which are published here; and a few other papers have been added to the volume from people unable to attend, filling further gaps in the published record. The emphasis, however, is on eastern Europe and Russia, regions not well covered in previous reviews. The book therefore provides much new information on current status and trends, updating some earlier studies and presenting the first published information from others. Some of the papers describe studies based on ringing programmes, and provide much new information on key demographic parameters, such as natal dispersal and adult survival. Among others, we have interesting papers on the reestablishment of a tree-nesting population in eastern Germany, on the use of PIT tags to identify individuals in Scotland, and on the well-studied population in a largely urban area of North Rhine-Westphalia with one of the densest Peregrine populations in the world, 92% of pairs nesting on buildings. It is perhaps just as well that Peregrines have now taken to nesting on buildings on such a widespread scale, for in some regions many of the traditional nesting cliffs have been taken over by Eagle Owls which have also increased in recent decades.

This volume follows three other landmark publications emerging from the United States, which dealt mainly with Peregrines in North America, but also included papers from Europe and elsewhere (Hickey et al. 1969, Cade et al. 1986, Burnham & Cade 2003). As a result of these various edited volumes, and many other papers published over the years in scientific journals, the Peregrine has retained its position as one of the best known birds in the world, with all aspects of its ecology having been investigated in many different parts of its range.

The current volume will prove of value to all Peregrine researchers, whether they are professional biologists, research students, or other enthusiasts, and a source of inspiration to others yet to come. The book will also add substantially to the baseline of knowledge on which future studies can build, and against which future changes in the Peregrine’s fortunes can be assessed. It nicely complements the previous volumes, and is a tribute to all involved: the organising committee chaired by Janusz Sielicki, and the editors of the volume (J. Sielicki & Tadeusz Mizera), but especially all the Peregrine enthusiasts who contributed to the meeting and the publication.

Vive le Faucon Pèlerin!

by Tom J. Cade

Like many contributors to this important book, much of my life has been devoted to observing and studying Peregrine Falcons. I saw my first wild Peregrine on Thanksgiving Day 1943 along the shore of San Dimas Reservoir in the foothills above Pasadena, California, when I was 15 years old. An adult female dove down over my head, whistling like an artillery shell as she sped by, and struck a coot dead as it flapped and paddled over the water in an attempt to rise into the air. Having read about John and Frank Craighead’s exploits with birds of prey, I knew instantly what she was and that I would never see any other birds as spectacular and as perfect as she and her kind.

The year 1943 also saw the publication of Casey A. Wood’s English translation of Frederick II of Hohenstaufen’s treatise De Arte Venandi cum Avibus. Dr. Alexander Wetmore, Secretary of the Smithsonian Institution, recommended that I read it. I became a falconer, because I knew doing so would put me in the closest possible contact with the bird I so admired. Like the great Emperor himself, whose book I read and re-read so avidly, and like many other falconers too, I was led to a deep and abiding study of nature and natural history through falconry.

I climbed into my first eyrie at Chatsworth Reservoir in 1944; it had already been robbed. In those days the Peregrine—ignorantly named “duck hawk”—was not protected by law and was considered vermin by gun hunters and pigeon keepers. Later, I traveled to Alaska and spent 10 magnificent and unforgettable summers studying nesting Peregrines and Gyrfalcons along wilderness rivers such as the Yukon, Tanana, Colville, and the Jago in what is now the Arctic National Wildlife Refuge. Peregrines were common along these rivers, as they are again today.

After my return to southern California in the 1950's, I joined a local group of falconers. We soon became concerned by the fact that several long known Peregrine eyries appeared to be either no longer occupied, or held eggs that did not hatch, and fledged few young. Although we did not understand it at the time, we were observing the deleterious effects of DDT on falcon reproduction. The Southern California Falconers’ Association was not only successful in obtaining recognition of falconry as a legal method of hunting in California, the first state to do so, but it also joined forces with conservationists and professional ornithologists to secure legal protection of the Peregrine Falcon. Only two other states had done so at the time.

In 1965, I participated in the pivotal International Peregrine Conference convened by Professor J. J. Hickey at the University of Wisconsin. There Peregrine experts learned, for the first time, of the full extent of the drastic decline in falcon populations in Europe and North America and of the role that DDT and other organochlorine pesticides played in causing this decline.

The rest of the story is familiar history. In 1970, the U. S. government officially listed both the anatum and tundrius subspecies of the Peregrine Falcon as endangered species, mainly in response to a petition submitted by falconers and falconer-biologists. In 1972, the Peregrine also joined all other members of the Order Falconiformes as federally protected species under the Migratory Bird Treaty Act; again, falconers were prominent in submitting testimony before several Congressional committees to secure this action. Also in 1972, the recently formed U. S. Environmental Protection Agency banned DDT for nearly all uses as a pesticide. Testimony about the effects of this chemical on the Peregrine Falcon, Bald Eagle, and other birds played an important role in this decision, which has held against occasional political attacks to the present day.

Shortly after the Madison Peregrine Conference, many falconerconservationists turned to the artificial propagation of Peregrines as a way to maintain a supply of falcons in captivity and to provide stock for reintroductions into regions where the species had disappeared or was greatly depleted in number. The success of this endeavor exceeded the wildest expectations of early proponents. Many thousands of Peregrines have been produced around the world. Nearly 7000 were released in North America, as well as others in Europe, notably in Sweden, Poland, and Germany, but also in scattered urban areas throughout Europe.

The response of the Peregrine to all these actions and protections has been truly phenomenal and unpredicted, just as its decline from the effects of organochlorine pesticides was also unforeseen in the 1950’s. Reintroduced populations are thriving in the eastern and mid-western United States, in some western states, southeastern Canada, Sweden, Norway and Germany. In portions of its range where the species totally disappeared for a time, Peregrines are back at least in their historical numbers in most places. In many parts of the range numbers now exceed the known historical abundance, sometimes by a factor of two or more, and habitats that previously were never, or rarely, occupied now have an abundance of Peregrines, especially in urban and industrialized districts. In many parts of its range the Peregrine continues to increase, so that we cannot yet predict what the final scope of its post-DDT expansion will be. Indeed, the Peregrine is now so common that it is again considered a species of vermin by devotees of shorebirds and pigeons, because of its supposed deleterious impacts on the numbers and behavior of these prey species.

In the United States the last populations (anatum subspecies) were removed from the list of endangered species in 1999. A few years later it became legal again to take a limited number of eyasses for use in falconry. In December of 2008, a limited take of passage Peregrines became lawful for the first time since 1969. Thus, the legal status of the Peregrine in the United States has come full circle, from one of the most completely protected birds in the 1970’s to one that is again under the management of the Migratory Bird Treaty Act, as a self-sustainable, renewable resource capable of producing a harvestable surplus of individuals additional to those annually required to replenish losses in the breeding stock.

As the collection of reports in this book reveals, interest in the Peregrine has not abated one iota since its recovery on two continents; indeed, it has intensified. The number of webcam sites on the internet focused on falcon eyries, revealing so many intimate details such as the mortal combat between females for possession of a nest site, the plethora of spectacular digital camera images showing new details of Peregrines in action (e.g., a falcon frozen in flying attack with legs fully extended and toes flared apart the instant before striking a pelican in the head), the satellite-tracking of migrating Peregrines, which can now be visualized topographically on Google Earth - all these applications of new technologies and others attest to the enduring captivation of the Peregrine Falcon, the ne plus ultra of nature’s winged hunters.

Peregrine Falcons and the literature

by Clayton M. White

Coming from North America my views on Peregrines were shaped by what I knew of them in North America. I have frequently felt uneasy about this because, after all, the Peregrine is a global species not just a species of North America. I felt at a bit of a disadvantage when it came to easy access to overseas literature and knowledge about them from distant countries. Was I missing something in the ecology of Peregrines because I did not know some of the literature often found in more regional or obscure Eurasian journals? Was I missing something about the status of Peregrines in countries foreign to me because I had difficulty with the enormously diverse languages throughout Europe? How could I find out who were the major players on Peregrine biology in overseas countries? To be sure, I could navigate rather comfortable through literature and knowledge of falcon enthusiasts in the UK, South Africa, and Australia because we had a common language. Thus, this conference is for me then a most exciting event because of the many gaps in my knowledge I can now fill. And while there had been two such previous conferences in North America dealing with Peregrines, both of which had information from a global perspective, this current conference is among the first with such a wide European geographical distribution of Peregrine information and papers all brought together in one volume.

I first met my friends and editors of this volume, Janusz and Tadeusz, at a similar but much smaller and less well publicized conference on the Peregrine held in Ciechocinek/Włocławek, Poland, in 1994. It was slated as the “European Peregrine Falcon Falco p. peregrinus – its status and future.” For those not familiar with the proceedings of that meeting, many of the papers were published in Acta Ornithologica Vol. 30, No.1, 1995, pages 4-105. The countries represented there were not nearly as expansive as at this present conference but nonetheless interesting papers were presented. Only a smattering of the topics in the present conference were given in the 1994 conference. Unfortunately some of the outstanding falcon investigators at the 1994 meeting in Poland, such as Vladimir Flint and Leo Stepanyan, have since passed away. I’m sure they would have been at this current conference and had much to offer. They are missed.

Several years ago Tom Cade asked me if I might be interested in undertaking an update of the Peregrine Falcon account in the handbook for The Birds of the Western Palearctic. He and his co-authors were going to tackle an update for the Gryfalcon. But then they only had to worry about data in the literature from Fennoscandia, Russia, and Iceland and use some comparative information from North America and Greenland. Not many countries to cover. The Peregrine on the other hand would have been a far different story. Now, after this present conference in Poland and recent data from an array of countries in eastern and southern Europe, would be the time to undertake an update for the Peregrine if it has not already been done.

Although information from over 25 different countries are presented there are a few unfortunate regional blanks. Because Peregrine numbers are so dense in Spain it would have been instructive to have a recent update for adjacent Portugal where densities seem to be much lower. With over 911409 square kilometres of land within Greece and Turkey combined, a significant chunk of Europe, this was an important gap in current information. With papers presented on Peregrines from Russia, India and Armenia, it is unfortunate that someone from the adjacent “stans” of Central Asia did not attend to present a current update. Real bonuses, however, are the papers from Tierra del Fuego and Kuril Islands. Early literature from the Kuril Islands by Bergman and Yamashina present a somewhat mixed view as to the distribution, density and taxonomic status of Peregrines breeding there.

The papers by Drewitt, Taranto and Molard, all dealing with urban Peregrines, are an important contribution. The curious recent expansion of Peregrines into urban landscapes in great numbers and on global basis awaits an adequate explanation. Cities with tall buildings have always been present but the numbers of locations with urban breeding Peregrines in past times have been limited. Perhaps a conference dedicated to urban breeding Peregrines would be timely. Much of their occurrence in North American and perhaps western Europe is probably related to the release of falcons in a reintroduction effort and the resulting behaviour of such Peregrines. But what explains their invasion of urban landscapes in such places as various cities in Australia, in Lima, Peru and in Kuala Lumpur, among other unlikely locations?

The new information in this current volume is much awaited by Peregrines addicts and will be appreciated by falcon enthusiasts of younger generations. The efforts of Janusz Sielicki and Tadeusz Mizera are to be congratulated as are the efforts of those that attended and participated in the conference. With the numbers of Peregrines soaring back globally life is good.

Peregrine Falcon populations
Status and perspectives in the 21st century
Edited by Janusz Sielicki and Tadeusz Mizera
ISBN 978-83-920969-6-2
Published by TURUL / Poznan University of Life Sciences Press, Warsaw / Poznan 2009
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