Part 1

Transcriber Note

Text emphasis denoted as _Italic_.

STRAY FEATHERS FROM A BIRD MAN'S DESK

STRAY FEATHERS FROM A BIRD MAN'S DESK

By Austin L. Rand

CURATOR OF BIRDS, CHICAGO NATURAL HISTORY MUSEUM

WITH CARTOONS BY RUTH JOHNSON

DOUBLEDAY & COMPANY, INC., GARDEN CITY, N.Y., 1955

_Library of Congress Catalog Card Number 55-5254_

_Copyright, 1955, by Austin L. Rand_ © _All Rights Reserved_ _Printed in the United States_ _At the Country Life Press, Garden City, N.Y._ _First Edition_

CONTENTS

PAGE Introduction 9 Birds Using Tools 15 Birds as Brigands 19 Birds Bathing 22 How Birds Anoint Their Feathers 25 Traveling Birds' Nests 28 Maladaptation in Birds 31 Feathered Baby Sitters and Co-op Nursery Nests 35 Birds' Nests and Their Soup 38 Walled Wives of Hornbills 42 Buried Eggs and Young 45 The Snowy Owl as a Trade Index 48 Monkey Birds 51 Bird-Made Incubators 54 Cormorant Fishing 57 The Shrike's Larder 60 Bird Flavors 63 How Many Feathers Has a Bird? 66 Last Year's Birds' Nests 69 Symbiosis--Animals Living in Mixed Households 73 Bird Apartment Houses 77 Bird Helpers at Nesting Time 81 A Name for a Boat 84 Weavers and Tailors in the Bird World 88 Social Parasites among Birds 91 Fish Eats Bird! 95 Crows Are Smarter Than "Wise" Owls 98 Tame Wild Birds 101 Birds as Pilferers 104 Hibernation in Birds 108 Snakeskins in Birds' Nests 111 Co-operation by Birds 117 Watchdogs at the Nest 121 Bird Guides to Honey 124 Oxpeckers 127 Wings in Feeding 130 Instrumental Music of Birds 133 Conditioning in Birds 136 Poisonous Birds 140 Kingfishers on the Telephone 143 On Identifying Sea Serpents 147 Conservation over the Telephone 151 Birds Washing Food 154 How Animal Voices Sound to Foreign Ears 157 Sight Identification 160 Green Hunting Jays Turn Blue 164 How Birds Use Cows as Hunting Dogs 167 Early Bird Listing 171 Battle of the Sexes and Its Evolutionary Significance 173 Water in the Desert 177 Bird Graveyards 180 Animal Gardens 183 Dropping Things 186 Learning by Birds 189 Can Birds Count? 192 Courtship Feeding 195 They Turned the Tables 198 Survival of the Unfit 201 Dust and Snow Bathing 204 Decoration in the Home 207 Curiosity in Birds 210 References 213 Index 221

INTRODUCTION

In looking back over the preparation of these sketches I feel as though each evening I'd gathered up the bits and pieces left over from the day's work and fashioned them into designs for my own amusement and the edification of my family. Truly it's as though I'd used stray feathers, fallen from the bird skins I'd handled, and fitted them together into something of wider interest than the original.

Much of my work now is museum research, working with bird specimens and books. In fashioning a research paper I always amass a great deal more material, that is to say, information and ideas, than I am able to use in it. In place of a lumber room I have a set of files with index headings that range from Abundance and Age, through such headings as Beauty, Feathering of Feet, Fictitious, Hysteria, Pterylography, Social, Song, Tail Feathers, Valentine's Day, to Zoogeography. Here I put the information that is irrelevant at the moment but too interesting to discard. Its source is varied. Some has been accumulated while studying specimens from localities as geographically separated as Alaska, El Salvador, Gabon, Tristan da Cunha, Nepal, Negros, and New Guinea; and while writing papers that range from describing new species to discussing secondary sexual characters and ecological competition. Some have been recorded while in the field on expeditions, trips that ranged from two years in Madagascar, three expeditions in New Guinea, and a season in the Philippines to trips nearer home from the Yukon to Nova Scotia, Florida, and Central America.

Gradually information builds up under each heading, and new ones are added. These items are too interesting to remain buried in the files. They are things people want to know about. So I began to draft them into articles for publication in the museum's monthly, _The Chicago Natural History Museum Bulletin_. The response was gratifying. The press picked them up and reprinted them. One was used in a Chicago _Tribune_ editorial. Several were used in commercial radio programs. Encouraged, I prepared more, soon overrunning the space available in the bulletin.

Most scientific papers are not written to be read for enjoyment. Conciseness as well as clarity are striven for, conveying certain information in a small compass. The correlations made are often obscure ones, appreciated only by scientists. Yet the material they contain is often intensely interesting, and if these papers were written in a more leisurely style, with more general correlations pointed out, they would provide both interesting and entertaining reading. In a few cases my own research falls in this class, and I've rewritten some of my own papers with this in mind (_see_ "Battle of the Sexes and Its Evolutionary Significance").

This collection of articles, if it were a painting, could be called a conversation piece. Or it might be compared to a well-filled whatnot. Each of the sixty chapters is an independent unit, illustrating some facet of birds, their behavior, or our study of them. Some of the facts may seem unusual or bizarre, but most of them are well known and well documented. The thing that is new, if there is anything new, is the setting in which I've placed them, the manner in which I've looked at them. Taken as a whole, they touch on many different birds from many different places in their less widely known aspects, and with a human interest slant.

"But what will your professional colleagues say?" asked a friend as he flipped through the cartoons. "These pictures don't approach the subject in a very serious manner." Quite true. But a discipline must be very lightly rooted indeed if it can't stand a few caricatures and cartoons and perhaps be the better for them.

The knowledge of most people about the hornbills of tropical Africa, the gulls of Australia, the penguins of Antarctica, and the crocodile birds of the Nile is probably pretty vague. To give a frame of reference in a biological sense is impractical in the compass of one slim volume.

But a ready-made frame of reference already exists: the parallels in bird and in human. These I have used. But in so doing I am not imputing human motives and attributes to birds. The actions are similar. The workings of the human mind I understand only vaguely; that of the bird I can study only through the actions of the birds. One set of behavior may be learned and rational, one rigidly innate, entirely instinctive, and inherited, or at most modified by experience. Be that as it may, the similarity in the end result in two such different vertebrate animals as man and bird when faced with similar problems is often close. Perhaps it is because the solutions are necessarily few; perhaps, and I incline to this feeling, it helps illustrate one aspect of the close relationship between all animate nature.

This series of articles is intended to be interesting and entertaining. I hope it will also make more people aware of the many ways birds act, here and in far places, how they have solved their problems and profited by their opportunities.

STRAY FEATHERS FROM A BIRD MAN'S DESK

BIRDS USING TOOLS

Man is the tool user pre-eminent in the animal world, but he does not stand completely alone in this. Here and there, in quite different groups of animals such as insects, mammals, and birds, a few kinds have forged a little ahead of the rest of their near relatives and show the very beginning of tool using.

The song thrush of Europe is perhaps a borderline case. It feeds in part on snails. To get the soft edible animal out of its shell, it carries or drags the snail to a favorite rock, its anvil, and there hits it against the anvil until the shell is broken and its contents exposed. The question is, can this be considered as using a tool? If the song thrush moved or prepared the rock, which it does not do, there would be no question that it was a tool. The sea otter brings a stone from the bottom of the ocean and places it on its floating body to use as a similar anvil in cracking hard objects, and this undoubtedly is the use of a tool. At the other extreme are many species of birds that beat their prey on branch or ground, wherever they happen to be. The song thrush is certainly an advance over that, and can, I think, be considered as using a tool in a primitive way.

A few other species, too, bring shellfish to special places. Gulls on our coasts pick up mussels and clams and, flying over a rock or some other hard surface, drop the shellfish, and follow it down. If the shell is broken, the dish is ready for the gull; if the shell is not broken the gull takes the shellfish up to a higher altitude and tries again. In places where hard-surfaced roads are conveniently located gulls have learned to use them as shell-breaking places, and such roads become littered with shells.

Crows of more than one species also use the same routine in breaking open shellfish, and they, too, have learned to use special hard surfaces, such as masonry walls, on which to drop the shellfish.

PAINTING A BOWER The satin bowerbird of Australia, a species known to science as _Ptilonorhynchus violaceus_, has also been considered as a case in point when discussing the use of tools. The birds are somewhat larger than a robin, the male glossy blue-black, the female greenish. The male of this species constructs an elaborate bower, presumably for courtship purposes. It makes it of sticks and twigs, and decorates it with bright and curious objects such as shells, feathers, bits of bone, and fruits, as do several other species of bowerbirds. But the satin bowerbird is unique in painting the inside of its bower. Fruit is crushed in its bill, and the bird, using its bill as the tool or paintbrush, smears the fruit juice on the sticks on the inside of the bower. While this is a wonderfully strange habit, and apparently unique in the bird world, it is doubtful if this behavior can be considered as using a tool. If the satin bowerbird used a twig, or a wad of moss or fiber, which it does not do, in spreading the paint, the case would be clear.

The clearest case is that of the woodpecker finch of the Galápagos Islands. _Camarhynchus pallidus_ is its proper name. It is one of a group of dull-colored finches restricted to the Galápagos Islands. Before it became known that one species used a tool, the chief claim to fame of the group was that it, along with some other Galápagos Island animals, such as the giant tortoises, had a great influence on Darwin's thinking which resulted in his working out the theory of evolution as set forth in his _Origin of Species_.

The woodpecker finch feeds largely on insects it gets by searching and probing on the ground, and on the trunk and leaves of trees. In searching crevices the woodpecker finch is handicapped by its rather short, thick bill, and to offset this, it picks up a slender, short length of stick, or the spine of a prickly pear, and with this in its bill, pokes into crannies. The insects, disturbed or driven out, are seized. Sometimes the woodpecker finch digs into the tree trunk and then gets a stick to probe with; sometimes it carries its probe about with it, poking in crannies until prey is disturbed. Then the stick is dropped and the food seized.

We have seen how several birds are perhaps borderline cases in using tools. They use certain special aspects of their environment in preparing their food, and use it time after time. It's probably instinctive behavior, but learning is shown in the gulls and crows coming to recognize and use a hard-surfaced road in breaking open their shellfish. The use of a probe by the woodpecker finch is a clear and unique case of tool using by a bird.

BIRDS AS BRIGANDS

Anti-social activities of humans such as those of brigands who plunder their fellow men find their parallels in the bird world.

The bald eagle is one of the best-known of the birds that practice such brigandage. Fond of fish, and capable of capturing it himself upon occasion, it is a common practice for the eagle to take fish from the osprey, plunder the osprey has just caught from the water. The osprey, with a fresh-caught fish, flies heavily. The watching eagle quickly overtakes the smaller, heavily laden bird and forces it to drop its catch, then dives down and usually catches the fish before it can strike the land or water. Rarely does the osprey escape with its food under such an attack. It is recorded that an eagle made several dives at one fish-laden osprey and, when these were not successful in making it lose its hold on the fish, the eagle dived under the smaller bird, turned over on its back, and with talons outstretched, snatched the fish from the grasp of the osprey and sailed away with it, as successful a pirate as ever sailed the seas.

NEMESIS OF VULTURES Besides taking fresh-caught food from the osprey the bald eagle has been seen pursuing vultures and making them disgorge their meal of carrion. The eagle, if unsuccessful in catching the disgorged food in the air, may land on the ground and eat it there. We know also that the aerial flights the eagle uses to frighten the vulture into relinquishing his food are not idle threats, for an eagle has been seen to strike and kill a bird that refused to disgorge.

Not only does our American eagle adopt such practices, but related species in other parts of the world behave in similar ways. The New Guinea sea eagle harries the osprey there, and on the west coast of Africa a sea eagle robs pelicans and cormorants of their prey.

Certain long-winged birds of the tropical seas, such as _Fregata magnificens_, are known popularly as man-o'-war birds or frigate birds, reflecting their well-known character as pirates and tyrannical freebooters. The man-o'-war birds get part of their food from many creatures which swarm at the surface of the sea, but they also get much of their food by forcing terns, cormorants, boobies, and pelicans to deliver up their catch.

In a tropical bay a school of small fish comes to the surface, perhaps driven by large fish below; from far and near terns gather, darting down to seize the fish that jump into the air. Above them circle the frigate birds, ready to dive down and chase and harry a successful tern until it drops its fish and leaves its prey to the freebooter.

BOOBIES ARE VICTIMS Frigate birds may sail about, also, where a colony of nesting brown boobies is located, waiting for the birds laden with food to return home. When such a food-laden booby returns, the frigate bird dashes down at it, buffets it with its wings, snaps at it with its long, hooked bill, until the booby finally drops its fish for the man-o'-war bird to enjoy.

The skua, a big, dark relative of the gull, is also known as a pirate. Its chief food is fish but it also eats many other foods from the sea. It rarely takes the trouble to fish for itself but watches until some other bird, perhaps a gull or a tern, has been successful in its hunting and then gives chase, forcing the unfortunate hunter to relinquish its food. Several of the skua's smaller relatives, the jaegars, have similar habits. It is written of the pomarine jaegar off our New England coast that they are notorious pirates and freebooters, the highwaymen among birds that prey on their neighbors on the fishing grounds and make them stand and deliver. The jaegar gives chase to a tern that has caught a fish and follows it through every twist and turn as if the two were yoked together. Finally the harassed tern drops its fish and the jaeger swoops down and seizes it before it can strike the water.

BIRDS BATHING

The toilet of most birds includes wetting their feathers in water and shaking the feathers and preening them with the bill. This bathing probably helps remove foreign matter from the birds' plumage and helps keep it in good condition. In addition it is probable that in summer the birds derive enjoyment from the coolness resulting from the bathing. But birds bathe in cold weather as well as warm and have been recorded doing so when the temperature of the air was only 10 or so degrees above zero.

The sparrows and robins that come about a birdbath usually hop right into the water. They squat down, fluttering their wings, and duck their heads into the water, splashing and rolling it over their backs. They may become quite drenched. Then they fly to some perch to sit and preen and dry their soaked feathers.

But some birds take shower baths. During a shower in late summer I have seen marsh hawks sitting in the rain with wings spread, apparently enjoying the wetting the shower gives them, and a buzzard has been recorded as deliberately flying to an open perch in a rainstorm and sitting there with its wings spread and sometimes shaking them until the shower was over, when it flew to a sheltered place.

SPRINKLERS A BOON The artificial showers of lawn sprinklers provide an opportunity for birds about our gardens to take a shower bath in fine weather. A robin or a flicker may hop into the shower and squat there and indulge in bathing antics on the wet grass. Hummingbirds have been seen to fly into the dense spray of a lawn sprinkler and hover there for a moment, gradually assuming a vertical position and spreading the tail, then slowly settling to the ground, and finally "sitting" on the grass, body erect and tail spread out fanwise, the wings continuing to vibrate slowly. In a few moments the bird may rise into the air and repeat the whole performance.

In wet tropical forest it is probable that many of the treetop birds bathe in the water that collects on the surface of the leaves, pushing their way through clusters of wet leaves and over wet surfaces of others until they are as wet as if they had actually been bathing in water. This is not restricted to tropical birds, for even in our latitudes towhees have been recorded as bathing thus, and thrushes and flickers have been seen to rub themselves over the wet grass and then go through the actions of bathing followed by preening.

BATHING WHILE FLYING Watching swifts or swallows coursing low over the surface of a lake and occasionally touching it leaves one with the impression sometimes that the birds are bathing rather than picking up insect food or drinking. With some other birds the habit of bathing from the wing is more definite. Sometimes drongo shrikes that are sitting up on a perch near the edge of a pool will fly out over the water, drop directly into it with a little splash, and then rise and fly back to their perch, where they either repeat the performance or sit and preen their feathers.

POST-PRANDIAL ABLUTIONS Ospreys have been recorded as bathing while on the wing in a rather striking manner. They have been seen flying along just above the surface of the water, then descending into it, adopting a sort of vertical American-eagle attitude while flapping the wings, then rising a little, flying on, and repeating the process. It has been suggested that the osprey is washing its feet in this manner after finishing its meal. One observer makes this still more definite. He says that the osprey finishes its meal of fish on a perch in a tree and then flies low over the lake. Dropping both its legs, the osprey drags them through the water, flapping its wings all the time. Then it immerses its beak and head into the water while still flying along, apparently washing off the scales and slime that it had gotten on itself while making its meal of fish.

HOW BIRDS ANOINT THEIR FEATHERS

A bird's plumage receives a great deal of care from the bird that wears it. The bill is the only implement for this grooming, and it is run through and along the feathers it can reach, helping clean them and making sure they lie in their proper place in the bird's dress. There are parts of the plumage that the bird's bill obviously can't reach, as that of the head, but ducks at least surmount this difficulty by rubbing their head against their body.

Many birds have oil glands (the only external glands that most birds have), a pair of glands just above and in front of the root of the tail, on the back. They contain an oily substance, and the usual explanation of its use is that the secretion of these glands is used in dressing the feathers. Certainly birds that have oil glands seem to use them, nibbling at them as though to press out the oil, touching them with the bill, and then rubbing the bill through the feathers, and rubbing the head against the oil gland.

The beautiful, soft, whitish bloom seen on some birds' feathers, such as the pale gray of a male marsh hawk and filmy appearance of some herons' plumage, is caused by specialized feathers called "powder down." Sometimes this powder down is scattered through the plumage; sometimes it is in patches, such as the particularly conspicuous ones in the herons. The tips of the powder down are continually breaking off and sifting over the rest of the plumage, giving it the bloom that with handling quickly rubs off.

WALNUTS AS A COSMETIC But birds sometimes rub foreign substances over their feathers--just why we don't know. Grackles have been known to use the acid juice of green walnuts in preening.