Bird-Lore March-April 1916.

by Various.

The World's Record for Density of Bird Population

By GILBERT H. GROSVENOR

Editor of the National Geographic Magazine

With photographs by the author

In the winter of 1913, our family bought a farm of one hundred acres, fifty acres in forest and fifty in fields, in Montgomery County, Maryland, about ten miles from Was.h.i.+ngton. We moved out in April. At the time, no members of the family, including my wife, six children, and myself, could name more than three birds--the Crow, the Robin, and the Turkey Buzzard. We had, however, become interested in birds, owing to our friends.h.i.+p for the Editor of BIRD-LORE, and for other Audubon workers, and determined to see what we could do to get birds around the home, which we named 'Wild Acres.'

The house is a typical old farmhouse, surrounded by an old apple and pear orchard, with vegetable garden and hedges, and open fields beyond.

Surrounding the fields is a tract of fifty acres in woods, with a beautiful stream, and several springs scattered around in the fields and woods.

The first thing we did was to drive away the English Sparrows which had possession of the place. We got small shot-guns, and, whenever a Sparrow appeared, shot him. It wasn't long before those that were not shot, left. We then made houses for Martins, Wrens, Bluebirds and Flickers, some of which were immediately occupied. We had such success that in the winters of 1914 and 1915 we put up more houses, and in the spring of 1915 had attracted so many birds around the house that Dr. H. W.

Henshaw, the Chief of the U. S. Biological Survey of the Department of Agriculture, became interested, and delegated Dr. Wells W. Cooke to visit our place. Dr. Cooke was so impressed by the number of feathered friends that we had gathered around us that he urged me to make a census of the birds living on an acre or two adjacent to the house, as he thought it probable that a count would bring us a world record. The record up to this time was held by a family in Chevy Chase, Maryland, who had attracted thirteen pairs of birds to one half-acre.

[Ill.u.s.tration: A BLUEBIRD'S NEST BOX, IN WHICH A PAIR OF BLUEBIRDS REARED THREE BROODS IN 1914, AND AGAIN IN 1915]

The prospect of securing a world's record was so inviting that, during the last week of June, 1915, I made a census of all birds nesting on the acre adjoining our house and barns, with the result that we found fifty-nine pairs of birds with young or eggs in the nest on that acre, the highest number of land-birds inhabiting one acre that has yet been reported to the Department of Agriculture or to any Audubon society. The details of the census are presented below:

LIST OF BIRDS NESTING ON ONE ACRE ADJACENT TO THE HOUSE AND BARNS OF GILBERT H. GROSVENOR IN THE WEEK OF JUNE 15-21, 1915

(Only pairs whose nests were located with young or eggs in them are counted.)

Flicker* 1 pair Bluebird* 1 "

Yellow Warbler 1 "

Orchard Oriole 2 "

Catbird 2 "

Song Sparrow 1 "

Chipping Sparrow 2 "

Phoebe 1 "

House Wren* 14 "

Robin 7 "

Robin 7 "

Kingbird 1 "

Martins* 26 "

-- Total 59 pairs

English Sparrows 0

The asterisk (*) indicates pairs nesting in boxes put up by the family.

A similar census made of the second adjoining acre showed thirty-three pairs nesting in this area, as follows:

LIST OF BIRDS NESTING ON SECOND ACRE

Song Sparrow 1 pair Carolina Wren* 1 "

Flicker* 1 "

Maryland Yellow-Throat 1 "

Brown Thrasher 1 "

House Wren* 4 "

Robin 2 "

Catbird 1 "

Chipping Sparrow 1 "

Screech Owl* (no young in nest June 15, as brood had already left) 1 "

Martins* 18 "

Towhee 1 "

-- Total 33 pairs

English Sparrows 0

[Ill.u.s.tration: A MARTIN HOUSE IN THE MEADOW, ABOUT ONE HUNDRED YARDS FROM THE HOUSE

It is advisable not to place the Martin box too near the house, for the birds begin to chatter long before dawn, and will awaken the household.]

[Ill.u.s.tration: MARTIN HOUSE IN THE HEN-YARD OCCUPIED BY TWENTY-FIVE PAIRS OF MARTINS IN 1914 AND 1915.

The Martins are very efficient guardians of our chickens. I have often seen them drive the Hawks and Crows away. They hate Buzzards also.]

I attribute our success primarily to shooting the Sparrows and driving all cats away, to putting up many boxes, to keeping fresh water handy at all times, etc. We did everything we could for the comfort of our birds; for instance, we put on twigs little pieces of the oil-paper that our b.u.t.ter was wrapped in, and we left mud in convenient places for the Martins. The Catbirds used the oil-paper for their nests, in fact, they used all kinds of sc.r.a.ps. Imagine the delight of the family when, on examining one of the Catbird's nests in the autumn, we found one of the children's hair-ribbons, and also a piece of an old dress of the baby!

[Ill.u.s.tration: A SCREECH OWL'S NEST

This box was put up for Flickers in the winter of 1914. Flickers took possession in March, but were driven out by Sparrow Hawks. But the Sparrow Hawks were frightened away two weeks later by the too great prominence of the position. Later a pair of Screech Owls adopted it for their home. Last winter we took the box down and carried it to the barn, to serve as a model for making other boxes. On opening it we found a live owl inside.]

[Ill.u.s.tration: A SPARROW HAWK'S NEST ON THE EDGE OF THE WOODS

We had much difficulty in keeping red and flying squirrels out of the houses placed near the woods. In 1915 red squirrels drove out a pair of Flickers brooding in a box on the forest edge.]

We had read a great deal about how tame birds become when they are protected, but were constantly amazed at the quickness with which they perceived the care taken of them. Perhaps the most remarkable nest was that of a Phoebe, which was built under the cornice of the piazza, within reach of my hand. We had a little school in the morning at the house, and ten children were continually running up and down the piazza, shouting at the top of their voices, but the Phoebe went on building her nest, then hatched her eggs and fed her young without fear, though she could see everyone and everyone could see her.

I was also surprised to find how friendly birds, even of the same species, can become. For instance, we had fourteen pairs of Wrens on a single acre, some of the nests being not more than fifteen feet apart.

We also had Robins nesting only twelve yards apart. The Bluebirds, on the other hand, do not like each other and would not tolerate another pair of Bluebirds nearer than 100 yards.

[Ill.u.s.tration: A FLICKER WAS NESTING IN BOX AND DID NOT STIR, THOUGH THERE WERE FIVE CHILDREN IN THE TREE AND FOUR BELOW WHEN THIS PHOTOGRAPH WAS TAKEN. (June 7, 1914.)]

[Ill.u.s.tration: AN APARTMENT HOUSE FOR WRENS

When we started building houses, we did not realize that Wrens would not share a house with another pair of Wrens. This house has rooms for eighteen pairs of Wrens. The room on the left was occupied in 1913, 1914 and 1915, and all the other rooms were vacant. Note Wren on box.]

[Ill.u.s.tration: A WREN HOUSE IN THE GARDEN

Note the Wren on the perch. We had fourteen pairs of house Wrens nesting on one acre adjoining the house and barns in 1915. This is the largest number reported of Wrens living on one acre.]