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Part 5. NovEemMBER, 1910.

THE

BRITISH WARBLERS

A HISTORY WITH PROBLEMS
OF
THEIR LIVES

BY

aw)
Tel SOE BO Noses Dy ¥.Z.S., M.B.O.U.

ILLUSTRATED BY HENRIK GRONVOLD

Donoon
R. H. PORTER
7, PRINCES STREET, CAVENDISH SQUARE, W.

Price 21s. net.

SMNTHSONTaye

AUG 29 1974
LIBRARIES

JAN 23 1986

HD nnnwLo

CONTENTS.
THXT.

Reed Warbler . pp. 1—61
Melodious Warbler ... Reel eh 19)
PLATES.

Reed Warbler, ad. and immature (coloured).

a > variety ad. re
Great Reed Warbler wae ks
Melodious Warbler ee sf
Aquatic Warbler PRA wats is
Whitethroat ad. g and ,, @’s (Photogravure).
55 sre eh oe *
Reed Warbler Hee Rs
99 9? ‘1)) 3b ”
? be) 9) os >)
TWO MAPS.

Showing approximate Geographical Distribution of Reed Warbler,
Marsh Warbler and Great Reed Warbler during Summer
and Winter.

—

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20

REED WARBLER.

Salicaria arundinacea, Hewitson, British Oology, 1st Ed., vol. i,
1 p., pl. 70, fig. 1 (egg), 1834.

Sylvia arundinacea, Meyer, British Birds, folio Ed., vol. i. (coloured
plate figuring adult and egg), 1835.

Calamoherpe arundinacea, Macgillivray, British Birds, vol. ii,
pp. 395-396, 1839; Gould, Birds of Great Britain, vol. ii,
2 pp., pl. 73 (coloured figures of adults), 1862.

Salicaria phragmitis, Hewitson, Hggs of British Birds, 2nd Ed.,
vol. i, p. 87, pl. 25, fig. 2 (egg), 1846.

Salicaria strepera, Hewitson, Hggs of British Birds, 3rd Ed., vol. i,
pp. 119-121, pl. 32, figs. 1 and 2 (eggs), 1856 ; Booth, Rough
Notes, vol. ii, pp. 45-46, 1883.

Acrocephalus streperus, Yarrell’s British Birds, 4th Kd.,
edited by Newton, vol. i, pp. 869-375 (woodcut), 1873;
Dresser, Birds of Europe, pp. 567-572, vol. ii, pl. 87 (adult),
1877; Lilford, Coloured Figures, vol. iii, p. 36, pl. 18,
(coloured figures of adult male), 1886; Sawnders, Manual of
British Birds, 2nd Kd., 79-80 (woodcut), 1897.

Acrocephalus arundinaceus, Seebohm, British Birds, vol. i,
pp. 367-374, pl. 10, fig. 16, 1883.

Croatian, Trsterjara parva ; Danish, Rorsanger ; Dutch, Kleine Karekiet ;
French, Fousserolle effarvatte; German, Teich-Rohrsdinger ; Hungarian,
Kis Nadirigo ; Italian, Cannajola Minore ; Swedish, forsangare ; Russian,
Trostnikowaja Kamzschefka; Spanish, Tazaret pinzoleta.

DESCRIPTION OF THE PLUMAGE.

Adult Male in Spring.—The upper parts generally are
brownish, washed with russet, but rather more reddish brown
on the rump and slightly darker on the crown. The wings
and tail are brownish grey, the larger feathers being edged
with the same colour as the back, though rather lighter. The
lores are light brownish ash, and the sides of the head brownish
erey. The throat and abdomen are white, the upper breast
being suffused with a very hght greyish buff, whereas the
flanks are of a more russet buff and the under tail-coverts
whitish buff. The underside of the tail and wings is greyish
lavender, the shafts of the feathers being white. The axillaries
and under wing-coverts are of a rich buff colour. ‘The iris is
dark brown and the feathers round the eye whitish. ‘The
upper mandible is blackish brown and the lower flesh colour

1

BRITISH WARBLERS

though somewhat darker near the tip; mouth and tongue are
orange yellow, the latter rather more red at the base, and the
feet and toes lavender flesh colour.

The general colour of the female is similar to that of the
male.

Adult Male, light variety.—I have given a figure of this
bird, which I obtained in Worcestershire, because the colouring
is so similar to that of the Marsh Warbler. The colour is
paler brown and less russet than the usual colour of the species,
the flanks and under tail coverts being whitish buff instead of
light russet buff, and the rump a slightly paler brown than the
back.

Nestling.—The upper parts are rich brownish buff, wings
slaty brown, the larger feathers being margined with the
same colour as the back, and the throat and upper breast the
same hue as the upper parts. The flanks are buff, abdomen
whitish buff, under tail-coverts light buff with a slight tinge
of russet, and the tail slaty brown. Iris is dark greyish
brown and the eyelid slaty ash. The upper mandible is
greyish lavender and the lower light lavender flesh. The
colour of the mouth is similar to that of the adult. The legs
are light lead colour, soles olive yellow, and claws olive grey.

GEOGRAPHICAL DISTRIBUTION.

Over the greater part of South and Central England it is
generally distributed, but westward becomes scarce in North
Devonshire, and rare in Cornwall and the Scilly Isles. In
Derbyshire it breeds in the Trent valley only, and it is found in
parts of West Lancashire and Hast Yorkshire, but from West
and North Yorkshire, Cumberland, Westmorland and North-
umberland it is absent, and from Durham there is only one
record. Across the Border it is almost unknown, the only record
being one from Fair Isle. In North Wales it is local and rare
except on the Shropshire border, and Anglesey does not appear
to be visited. In Brecknock it is fairly plentiful. There is no
authenticated record of its occurrence in Ireland.

2

VARIETY

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REED WARBLER

Over the greater part of Europe this bird is a common
breeding species. In Spain it is found in suitable localities
which are few and far between, but it breeds near the mouth of
the Guadalquivir, and also in the Balearic Islands, while it is
very common in Portugal, but does not nest in Corsica and
Sardinia. Throughout France, Belgium, and Holland it is
generally distributed and abundant, and the same may be said
of Denmark, but in Southern Sweden we reach its northern
breeding limit at Lake Wener, nearly 59° N. lat.

To Germany it is a common summer visitor, though less
plentiful in some of the eastern provinces, and in all suitable
localities in the Austro-Hungarian Monarchy it is numerous.
In Switzerland we find it common and breeding even in the
Alpine valleys at an altitude of 4,000 ft., and it also visits Italy
and Sicily in large numbers, and is again numerous in many
parts of the Balkan Peninsula, but has not been proved to
breed in Greece. In Poland it is common, but the southern
parts only of the Baltic Provinces are inhabited, and it is
again common in the provinces of Volhynia, Kiev, Tcher-
nigov, Poltava and Podolia, and occurs throughout Southern
Russia generally, and probably also in the Crimea. From the
northern slopes of the Caucasus there are no records, but on
the southern slopes it has been found near Tiflis and Lenkoran,
and it appears to visit Astrakhan and the Uralian Cossacks in
large numbers.

There are also records of its occurrence from the Trans- —
caspian Province, Turkestan, and the Altai Mountains,

In parts of Asia Minor it is not rare, and has bred in
Cyprus, Baluchistan and Persia.

Of its winter quarters in Africa we have yet much to learn,
but its range appears to be an extensive one, since it occurs as
far south as Rhodesia, the Orange River Colony, and perhaps
even Cape Colony.

It is also recorded at this season as visiting Greece, Asia
Minor, Palestine, Persia and Baluchistan.

BRITISH WARBLERS

LIFE-HISTORY.

The home of these birds is principally among the common
reed (Arundo phragmites), which grows in such profusion on
large pools and lakes, along the banks and in the backwaters
of many rivers, in canals, and in all marshy ground where
there is a sufficient depth of water. And owing to the fact
that reeds grow in such dense masses, the habits of
this species are at all times very difficult to study. Even
at the commencement of the season, before the young reeds
have attained to any height, it is by no means easy to keep
one individual continually in view, and if this is not done
some small incident, unimportant perhaps in itself, may escape
observation, without which, however, an accurate interpreta-
tion of its actions may be impossible. When the nest is
built and the parents are incubating or tending their young,
their habits are the more easily studied, for they are not
shy nor retiring like so many species, but rapidly overcome
any diffidence they may at first show when a human being
is near the nest. It is even possible to cut away the reeds
immediately surrounding the nest so that an uninterrupted
view of their actions may be obtained, without in any way
exciting their suspicions or hindering in the least a proper
carrying out of their parental duties.

In the Midland counties their arrival may be expected
during the first week in May; this remark refers to the
forerunners of the band of migrants, which appear to be
always males. The migratory movement as a whole is
peculiarly erratic and somewhat difficult to understand; not
that the time of advent of the first males varies very much,
but that males and females intermingled continue to arrive, and
to pair so long as there is sufficient territory, for some weeks
alter the arrival of the first male. It is sometimes suggested
that the advent of the first individuals depends upon the
state of growth of the reeds. Perhaps this may be true
when a comparison is made between the dates of arrival
in countries some distance apart, but the difference in the

dt

REED WARBLER

erowth of the reeds from year to year in the second week
of May in this country is slight, and does not appear to me
to be sufficient to influence their movements. Moreover, it
is not possible for a species in a foreign land to be cognisant
of the state of growth of the reeds in these islands. If it
can be shown that there is any relation between the two,
an explanation must be sought in some peculiar climatic
conditions which, while delaying the departure of the
migrants, would at the same time retard the growth of
the reeds. In Hungary I found these birds plentiful in the
year 1905 on April 26th, and there is little doubt that they
had already been there some time. On the other hand, I
have no records of their arrival in this county earlier than
May 1st. In the year referred to, the growth of the reeds in
Hungary was undoubtedly in advance of the growth in this
country. So that before we attempt to understand this
question of migration, we must be in a position to decide
whether, on the average, the same individuals migrate to the
same country year after year. There are some grounds for
believing that they do so, for it is clear that those individuals
that reach Hungary about April 20th must have commenced
their journey some time before those that reach this country
during the first week in May.

Both males and females arrive throughout May and part
of June, even as late as the 21st of the latter month. But
it is by no means unlikely that some of the individuals are
not “arrivals” in the sense of having only completed their
journey that particular day. Indeed, it is impossible to
distinguish between a male moving from pool to pool seeking
territory, or similarly a female in search of a male, and a
true arrival, that is to say, a bird that has only comparatively
recently commenced to travel from its winter home. These
later arrivals may not, therefore, be migrants in the narrower
use of the term, but only individuals unsuccessful so far ag
reproduction is concerned. Yet it is well-nigh impossible to
decide this by actual observation. Their plumage has no

5

BRITISH WARBLERS

worn or ragged appearance, but the colouring is brilliant and
the feathers in perfect condition, in striking contrast with
those birds that have actually commenced to breed some
weeks previously. The deterioration of the plumage is
coincident with, if not actually the direct result of, coition,
for it takes place very slowly when a bird is not breeding,
but rapidly immediately reproduction has commenced. Never-
theless evidence of a much more detailed character is necessary
before we can reach a final decision on this point. It even
appears to be more rapid in some species than in others, being
decidedly so in the case of this warbler, some individuals
commencing their moult early in July. So that we find, on the
one hand, members of the species arriving about June 20th in
perfect plumage, and thereupon commencing to breed, and on the
other, members commencing to moult early in July, having
finished the task of reproduction. Thus we have what appears
to be a curious irregularity, and one to which I shall refer
again.

The Arundo phragnutes is the principal but not the sole
haunt of these birds, for they often frequent and build amongst
the various species of Saliz that grow along the banks of
rivers, and on their way thither, or when in search of a terri-
tory, the males sometimes rest for a few days, or a few hours,
in such places as osier beds, or even amongst the shrubs in
gardens; but in such places they are merely sojourners,
although they sing as vigorously as if they were in possession
of a territory. They commence to sing on the morning after
their arrival, and as they are the most persistent of singers,
there is little difficulty in assuring oneself of their presence in
any particular reed bed. ‘This is especially the case before the
females arrive, as they then sing almost incessantly through-
out the first few hours of daylight, commencing at dawn and
only lapsing into silence for short intervals. At this time of
day they can often be seen perched on some horizontal reed
pouring out their peculiar metallic sounding notes, or preening
their feathers, their attitude at such a time being much like

6

REED WARBLER

that of the Blackcap when quietly reposing, back feathers being
raised, tail drooping, and breast feathers swollen out, giving
them a similarly rounded appearance.

Owing to the density of the reeds, and consequently the
creat difficulty in studying their habits, I do not think it likely
that I should ever have recognised any law of breeding terri-
tory, had I not previously known of its existence amongst so
many other species, but there is little doubt that this question
plays an important part in their life-history. Hach male
locates himself in a particular part, and a comparatively small
part, of the reed bed, and inasmuch as reed beds suitable to
their needs are not very plentiful, the dimensions of their
territories are small. If it were not so the species would
rapidly decrease, so that they differ in this respect from those
migrants that inhabit many and varied situations. The
males adhere more or less to a certain territory, but it is
not easy to ascertain how far they struggle with one another
for possession, nor whether they regard with suspicion a
trespass on the part of one of their neighbours. Short but
anery battles are of frequent occurrence between them for
some weeks at this period. One hears the clicking of bills,
and then the birds appear momentarily above the tops of the
reeds, pecking at one another, and as quickly vanishing
amongst the reed stems, only to reappear further away as
they rapidly pursue and fight with each other. In one instance
I had an exceptional opportunity of watching the behaviour of
a male with regard to this question of territory. This par-
ticular bird owned a territory amongst some willows and
alders adjoining a reed bed, the headquarters of his domain
being a Saliw bush overgrown with honeysuckle, and not more
than fifteen yards away on the edge of the main portion
of the reed bed was the territory of another pair. This latter
pair must have arrived some few days before the former bird,
because, when I commenced to watch the two territories on
May 22nd, they were already building their nest. Morning
after morning this single male behaved in much the same

q

BRITISH WARBLERS

way, singing continuously while perched upon the sunny side
of the bush which he had made his headquarters. If a single
bird or one of another pair attempted to intrude upon his
small domain, he fiercely attacked it, rapidly pursuing the
trespasser some distance into the dense mass of reeds, and
when a collision did occur the impact was considerable. If it
was a pair that was intruding the attack was generally aimed
at the male, but the female from the adjoining territory, while
collecting food for her young, was also attacked. Thus the
days passed by, sometimes peaceably, sometimes the reverse,
until this jealous defence of his territory seemed to me to be a
waste of energy and time, as it appeared to be improbable that
a female would arrive at so late a date. In this, however, I
was mistaken, for on June 20th a female appeared on the
scene, and nesting operations were forthwith commenced.
His behaviour now differed from what it had been previously;
the headquarters were of secondary importance, and he now
followed the female submissively. It is an interesting fact,
and not a little curious, that on the day on which the female
arrived—June 20th—the young of the adjoining pair finally
left the nest. Why should this male for twenty-eight days have
remained in the same small plot of ground? Why should
he day after day have been found in the same bush and upon
almost the identical branch pouring out his song? And above
all, why should he have resented the approach of other mem-
bers of his own species, and have attacked them so viciously ?
I have already mentioned this question of breeding territory in
the life of other species. It is, I believe, a factor of no small
importance in the animal kingdom, and as such demands
further consideration.

Those who have paid attention to the habits of birds during
the season in which the sexual organs are developing
can hardly have failed to notice the battles which are of
such frequent occurrence between the males of the same
species. Darwin believed that the primary object of these
struggles was the possession of a female, but for reasons

8

REED WARBLER

which I shall presently give, I am inclined to think that the
possession of a territory is of greater importance to the male,
and is the direct cause of these struggles, which are conse-
quently presented to us in a somewhat different light.

I well remember some years ago in the month of March
being attracted by piteous cries which were proceeding from
some willows that grew in an old bed of the River Severn.
Quietly approaching the spot, I saw a male Blackbird (Turdus
merula) hopping about in front of a small clump of dead
vegetation, into the middle of which he was at short intervals
angrily darting, and from which, as he thus darted forward,
there arose the cries referred to. After watching the proceed-
ines for a short time, I examined the dead vegetation and
there found another male Blackbird crouching beneath the
dead grass, in such a state of exhaustion as to be unable to
stand, but only to roll from side to side, the feathers torn from
its head, and traces of blood showing how severe a punishment
had been administered. Jaising it carefully from the ground,
I removed it some distance away, hoping that it might even-
tually recover. very spring the male Blackbirds can thus
be seen engaged in desperate struggles. In lke manner male
Song Thrushes pursue and fight with one another, bunches of
feathers being sometimes left upon the scene of the conflict.
Male Chaffinches (fringilla celebs) fight in mid-air and upon
the ground. The males of the Coot (Fulica atra), and Moor-
hen (Gallinula chloropus), frequently struggle amongst them-
selves, the latter both upon water and land. How pugnacious
the game birds become at this season is well known. I have
seen one cock Pheasant pursuing another in a grass meadow
for twenty minutes or more without a momentary pause.
But that such small and delicate little birds as the males of
the Long-tailed Tit (Acredula caudata) should engage in
violent contests amongst themselves will scarcely be believed ;
nevertheless it is the case. Walking in the month of April
along a country road, I noticed something fluttering a little
distance ahead of me, and upon reaching the spot found two

9

BRITISH WARBLERS

male Long-tailed Tits engaged in a fierce conflict ; the one had
seized the other by the feathers on the head, and in this way
they were rolling over and over on the ground. Frightened
ati my approach the stronger male of the two flew away, leaving
its opponent too exhausted to move. I picked it up, and
while examining its head noticed the aggressor still flying
round, evidently unwilling to leave. In order, therefore, to
ascertain whether it would still continue the conflict in my
presence, I placed its opponent again upon the ground, and
retired some few paces distant, upon which the attack was
renewed, and so severe was it that had I not again interfered
the exhausted male must shortly have succumbed to its
injuries. In the hope of saving its life I carried it some
distance away and placed it in the bottom of a hedgerow.
But it was then in a state of collapse, too weak even to stand,
and it is doubtful whether it ultimately recovered. As in the
case of the Blackbird, the principal point of attack had been
the head, from which the feathers were torn in places.

Battles somewhat of this description, but with differences
in detail, are of frequent occurrence at this season of the
year throughout bird life in general. And since they only
occur at this period, which is the period of sexual activity, it
was concluded—and it must be admitted that the conclusion
was not unnatural—that the females were the direct cause of
the quarrels. For many reasons, principal among which
was the fact that the females were seldom in evidence during
the battles, this conclusion never appeared to me altogether
satisfactory. The question was therefore always prominent
in my mind as to what was the real meaning of these struggles,
so terribly determined, and sometimes even resulting in the
death of one of the combatants; and it remained unanswered
until I began to make a special study of certain migratory
species. It is strange that the importance of their life-history
did not impress itself upon me earlier ; for it requires but little
reflection to show how splendid an opportunity is afforded in
their lives for studying some of the problems with which we

10

PUBLISHED BY R H. PORTER

MALE REED WAR BUER
ATTITUDE ASSUMED DURING THE
PERIOD OF SEXUAL ACTIVITY
THE SLIGHT EXPANSION OF THE WINGS
WILL BE NOTICED.

SWAN ELECTRIC ENGRAVING 0?

rida
oy
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REED WARBLER

are confronted. It almost seems as if Nature had thus supplied
us with a key to some of the mysteries of their existence.
The married life of the resident species is so gradually un-
folded each recurring season before our eyes, that we know not
with any certainty at what point sexual development com-
mences, and we can seldom indicate the precise moment at
which that mutual attraction between the sexes occurs which
ultimately leads to reproduction. But in the case of the
migratory species the conditions happily are different, for since
the spring migration is undertaken for the purpose of procrea-
tion, it is probable that the stimulus to that long and arduous
journey is the fact that the initial stage of the development of
the sexual organs has commenced. Moreover, males arrive
before the females, and this fact is of immense assistance in
helping us to trace out the true meaning of much of their
behaviour.

I found, then, that many of those males that were the
first to reach a certain district were not passing travellers only,
secking ous new woods or new swamps, and leaving their
places to be filled by later arrivals, but that they remained
more or less in that locality in which they had settled upon
their arrival ; and further observation went to show that this
locality was narrowed down to a certain territory, in which
the bird remained and sought its food, and which possessed
definite boundaries adhered to with remarkable precision, and
often, indeed, with an accuracy almost beyond belief. Further-
more I found that, when two males arrived more or less at
the same time in the same locality, a battle often ensued,
equally as desperate as those which occur amongst many
of the resident species at this season of the year; but inasmuch
as the females had not at that time arrived, it was clear that
they were not the direct cause of the quarrels; and, finally,
that in the case of adjoining territories whenever a male
crossed the boundary at any time during the period in which
the territories were adhered to, its action was generally re-
sented by the other male, and often led to a struggle. With

11

BRITISH WARBLERS

these facts before me I turned my attention again to some
of those resident species whose battles had previously been
a mystery. A small pool of water in front of my house
afforded exceptional opportunities for studying the life of the
Moorhen. This pool was inhabited by one pair, and not
only was no other Moorhen allowed to approach without
being attacked, but so jealous was the owner of any intrusion
that he ruthlessly persecuted such harmless species as Black-
birds, Starlings, and the like, when they came to the water
to drink. His method of attack was as follows: he walked
quietiy round the edge of the water, taking advantage of
every clump of rushes to conceal his approach, and when
within a few feet of the intruder, raised his wings, lowered
his head, and, in a threatening attitude, darted rapidly out.
In connection with this particular bird I once saw an amusing
incident. A covey of about twenty Partridges approached the
pool, but the Moorhen from his position was only able to
see the cock bird, who was leading. He therefore approached
in his usual cautious manner, and when finally on the point
of attacking was suddenly confronted with the remaining
birds, the majority of their heads being turned in his direc-
tion. The effect was instantaneous; he assumed his normal
position and retired into the rushes. On large sheets of
water, inhabited by a number of pairs, a similar law as to
territory will be found to prevail, each pair possessing a
certain area which they regard as their own property. The
habits of this bird render its life an especially suitable one
for comparative study and analysis, for, of necessity, a large
number are often concentrated in a small area. Therefore
if some pool is kept under daily observation early in the
spring, it will be found that towards the end of February,
that is to say, with the rise of the sexual instinct, quarrels,
sometimes developing into serious struggles, will be of
frequent occurrence between different individuals. And it
will be noticed that these quarrels, as a rule, have their
origin in one or two individuals, or pairs, which, keeping

12

REED WARBLER

respectively to certain parts of the pool, resent any intrusion
thereon, and that as the days pass by, the pool, upon which
formerly it was no uncommon sight to see eight or more
birds in company, will be inhabited by two or three pairs
only, each possessing a definite territory, and also that
they still jealously guard their respective territories, resist-
ing any intrusion on the part of their neighbours. In order
to see the struggles to the best advantage, it is necessary
that the pool should be kept under observation from daylight,
for, strange as it may seem, the conflicts appear to be of
more frequent occurrence at dawn; there are, in fact, some
grounds for believing that many a battle is fought and many
a territory won or lost during the hours of the night. So
strongly implanted is the law of territory in this species,
that a young one of not more than ten days old will attack
such a bird as a Starling when settled upon the edge of the
water, resembling the adults in its method of attack. Coots
(Fulica atra) also struggle fiercely for their territories, like-
wise Stonechats (Pratincola rubicola), and the attitudes
assumed by the male of the latter species when another
male, or another pair, approaches its property are extravagant
and often ludicrous. Both sexes of the Chaffinch are highly
pugnacious at this season, and their habits are easily observed.
This bird being a very common species, it often happens that
some small but suitable wood is inhabited by a number of pairs
and divided into adjoining territories. Early in March the
males establish themselves in a certain small area, and each
morning at daybreak can be heard vigorously pouring out
their song. When a female arrives in one of their territories,
there is considerable commotion. Sexual excitement takes
the form of prolonged flights. Rising above the tops of the
trees the female flies away, followed by the male, and often
a considerable distance has been thus traversed before a
return is made to the territory. As a consequence of this
the female, more often than the male, passes the boundary,
intruding upon the adjoining territory, and thus it happens

13

BRITISH WARBLERS

that she is sometimes attacked by the owner of that territory.
But if she is followed by the male with whom she has paired,
it almost always leads to a strugele. Considerable dis-
turbance may also be caused by two pairs whose territories
adjoin attacking one another. It is difficult to say with
any degree of certainty what is the cause of such battles,
though it sometimes seems to me possible to trace the origin
to some female, recently arrived, not confining herself to
the boundaries of the territory in which she has settled.
But whatever it may be, the conflicts, when they do occur,
are very fierce, the males and females attacking one another
respectively. ‘That Peregrine Falcons (Falco peregrinus) and
Ravens (Corvus corax) will not allow another pair to breed
in proximity to them is well known; and from the accounts
of other observers the same law appears to be in operation
in the case of the Red-necked Phalarope (Phalaropus hyper-
boreus), Waders, e.g., Ruff (Machetes pugnaxr), and the Black
Grouse (Tetrao tetriz). I have not yet had sufficient oppor-
tunity of studying the cliff-breeding sea birds to enable me
to bring forward any direct evidence from their lives, but
from what I have seen little doubt remains in my mind
that “acquisition of breeding territory” has exercised and
is exercising a considerable influence on their life-history.
How far this law extends it is impossible to say; the evidence
is sufficient to show that it holds good with many species,
and I shall not be surprised to learn that it is a vera causa
of the battles so common between the males of many species
of mammals and lower vertebrates.

In the life-history of the Whitethroat I have described
a struggle between the females, and the attitude of the male
in whose territory the battle was taking place, and I then
suggested that the struggle seemed to be one of some import-
ance to this theory. The females of some species are more
brightly coloured than the males, and in such cases it is they,
and not the males, that are pugnacious and fight with one
another. This is so with the Phalaropes. The female Moor-

14

MALE REED WARBLER
SWAN ELECTRIC ENGRAVING Cc?

PUBLISHED BY R.H.PORTER

REED WARBLER

hen is more vividly coloured than the male, and it is possibly
she who defends the territory, attacks all intruders, and
exhibits the pugnacity referred to, although it is difficult to
make certain of this, since the difference in colouring and
size between the sexes is so slight that at a distance it is
not very easy to distinguish them. The question: we are
attempting to answer is what is the cause of the battles, and
whether an individual of one sex does really strugele for
possession of one of the other sex. When the fighting is
confined to one sex only, we might be justified, providing
there were no evidence to the contrary, in assuming that the
opposite sex was the immediate cause. But in the case of the
Whitethroat we have a species in which the males are more
brightly coloured than the females and strugele amongst them-
selves, but in which, contrary to expectation, the females also
fight with one another. Of what advantage could it be to any
species for the males to struggle for the females, and for the
females to struggle for the males? ‘This fact of the females
fighting is therefore one of some importance, since it points to
the existence of some other factor as the true cause of the
battles. Among the large number of individuals that annually
migrate together, it must sometimes happen that two females
settle in the same occupied territory, and under these circum-
stances what could be more natural than that one should
attempt to drive the other away? The ultimate object of
such a battle may be said to be the male: this much I con-
cede; but another factor is introduced by the law of territory,
with the result that it matters not whether the male possesses
any special attractiveness, so long as the more important
consideration be fulfilled, namely, that he be the owner of a
territory. The question, then, which remains to be answered is
to what extent a law of battle does exist amongst the females.
I mentioned at the time that in no other species had I
seen the females fighting, but I have since been lucky
enough to see two more instances. Both sexes of the Moor-
hen aid in the defence of their territory, as do both sexes of

15

BRITISH WARBLERS

the Chaffinch, and, in the case of the latter species, the
females struggle fiercely together, their battles being as
desperate as those which occur between the males. I have
seen two individuals struggling intermittently for nearly half
an hour, and for the greater part of that time the fighting took
place on or near to the ground. There was no doubt that
the conflict was genuine; the rapid breathing, tightly drawn
feathers, the rolling over and over on the ground, and
the fluttermg up in the air, showed this only too plainly.
The male watched the contest from a branch above, and
occasionally interfered by flying into the arena, but whether
he attacked one bird only I was unable to ascertain; his
efforts were of little avail in putting an end to the battle.
This, then, is the sum-total of the evidence—insufficient,
perhaps, to justify any definite conclusion ; and there for the
present we must leave it. Butif there be any who think the
evidence unreasonably scanty, supposing the struggles of the
females to be a reality, I would ask them to consider this
point—one to which I shall presently refer with regard to the
males—that it is unnecessary for every individual to struggle
for a territory, and this must be even more true of the females.
It is not necessary, neither is it possible, for each female to
have a rival for the territory in which she has settled. Prob-
ably it will only occasionally happen that two females meet
in competition in any one particular locality, but if, when they
do so meet, the stronger gains an advantage, that is all that
will be required to maintain the strength of the species.

Our confidence in the truth of a theory must increase in
proportion to the number of observations which receive an
explanation under that theory, but not under any other. And
there are two observations which become intelligible under the
theory of breeding territory, but which, hitherto, have been ~
inexplicable. The first of these, and the more important, is
the fact of the males arriving at their breeding haunts before
the females. It has long been recognised that amongst the
migrants the first individuals to reach their destination in the

16

REED WARBLER

spring are almost invariably males. I have met with one
instance only in this district of a female arriving before a
male. In reference to this, Gitke writes in his “ Birds of
Heligoland” as follows: “In the spring in the case of all
species the most handsome old birds are invariably the first
to hasten back to the old homes as the heralds of reawakening
life; these are soon followed by the old females, whose
numbers increase, while those of the males decline, and the
migration is brought to a close by the younger birds.” It
must not be understood from this that the migration of the
males is completed before that of the female commences, but
that the migration of the sexes overlaps, males continuing to
arrive with females. It is important that this should be clear,
because there seems to be an impression that the times of
migration of the sexes are distinct, that the males arrive, and
that after a pause the females follow. For instance, the late
Professor Newton, referring to this peculiarity, says: “It has
been ascertained by repeated observation that in the spring
movement of most species of the Northern Hemisphere the
cock birds are always in the van of the advancing army, and
that they appear some days, or perhaps weeks, before the
hens.” And he then proceeds to give this explanation: “ It
is not difficult to imagine that, in the course of a journey
prolonged through some 50° or 60° of latitude the stronger
individuals should outstrip the weaker by a very perceptible
distance, and it can hardly be doubted that in most species
the males are stouter, as they are bigger, than the females.”
Had he known that the migration of the sexes overlaps, that
a few males arrive, forerunners of the advancing army, but
that afterwards males and females arrive intermingled, it is
probable that his interpretation would have been modified.
And even if it be granted that the males are the stronger, this
cannot account for their outstripping the females by a week,
ten days, or still less by a fortnight in a journey of perhaps
1,500 miles. To expect them to accomplish such a distance
in from four to five days is surely not estimating their

2 17

BRITISH WARBLERS

capabilities too highly, and any slight inequality in power of
flight or endurance could give the males an advantage of but
afew hours only. Darwin believed that the difference in the
periods of their arrival could be explained thus: “Those males,”
he writes, “which annually first migrated into any country, or
which in the spring were first ready to breed, or were the most
eager, would leave the largest number of offspring, and they
would tend to inherit similar instincts and constitutions.”
But why should those males that first migrated leave a larger
number of offspring? Reproduction could not commence until
the females arrived, consequently the males that reached
sexual maturity later and travelled in company with the
females would have equal, if not greater, opportunities for
securing a mate. There is some evidence to show that
throughout Nature there is a tendency for the males to reach
sexual maturity before the females, but this does not explain
why they undertake the journey so much in advance ; it
makes it, in fact, all the more difficult to understand. For
we cannot but believe that a male that had reached sexual
maturity would be all the more reluctant on account of its
own passion to desert the company of the females and travel
on to the breeding grounds, there to await their arrival. The
disadvantage in their thus hurrying forward is so obvious that
we can only conclude that there must be some advantage
correspondingly great, for they, above all others, are the
individuals that will be called upon to withstand the rigours
of an inclement spring, cold winds, and even blizzards, to
which countless numbers frequently succumb. This desertion
of the females and anxiety to reach the breeding grounds,
which is difficult to reconcile with the belief that the first
step towards reproduction is the finding of a mate, becomes
intelligible if we accept the principle of breeding territory.
Those individuals that hurried forward would, on the average,
be more likely to attain to reproduction, for they would have
the choice of territory, and the fact of being already in posses-
sion when other birds arrived would tell in their favour ;

18

REED WARBLER

moreover, they would have recovered from the fatigue of their
long journey, and would thus be in a better position to
struggle when challenged by a later arrival; Nature’s process
is therefore a simple one, requiring no recognition on the
part of the males of territories as such; their whole behaviour
can be accounted for otherwise—and, what is more important
still, without our having recourse to complex principles of
explanation.

A male, however, does not always have to fight for its
territory. It happens, and not infrequently, that its rights to
ownership are recognised, and only when these rights are
disputed, either by a later arrival, or by another male arriving
simultaneously, does a struggle ensue. Thus we have the
spectacle, as in the case of the Blackcap, of two or three males
following one another for a short time after their arrival,
finally separating amicably and taking possession of adjacent
territories.

A truer definition of the order of migration would be this:
Some males arrive before others, and some females arrive
before others, but males arrive before females. The same
factor which causes males to arrive before females is possibly
the cause of the discrepancy in the time of arrival of the
individuals of both sexes. We can of course say of the
females, as we can of the males, that the earlier arrivals are
probably the more vigorous; but this does not explain, any
more than in the case of the males, why one individual hurries
off before another. Moreover, if we accept such an explana-
tion, we are at once faced with a difficulty, and a very con-
siderable one, namely, that the stronger females and the
weaker males will travel in company. And if, for the moment,
we assume that territory has no control over reproduction,
what incentive would there be for the stronger females to seek
the stronger males scattered throughout the different districts,
and consequently what could possibly prevent their breeding
with the weaker males, thereby frustrating the very result for
which we all believe Nature is for ever striving, the mainten-

19

BRITISH WARBLERS

ance of the strength of the species? And if territory 7s an
essential to reproduction, and the final appeal for territory is
to the strength of the individual male through the law of
battle, of what use could it be for females to arrive before
males? On the other hand, if the first step towards reproduc-
tion is to find an unpaired male in possession of a territory,
what would be the position of a female that, from one cause
or another, was late in arriving at the breeding grounds?
The balance between these extremes, that is to say, between
a too early and too late arrival, must have been gradually
adjusted to suit the needs of different species.

The second observation is that which has reference to the
banishment of the young by the parents. Itis well known, in
the case of many species, that the parents drive away their
offspring as soon as they are able to take care of themselves;
and the reasons generally given for this behaviour are, firstly
that the supply of food would not be sufficient to maintain
both old and young, and secondly, that interbreeding would
thus be prevented. While it is no doubt true that both these
ends will ultimately be attained, yet neither one nor the other
can be the motive force which impels the parent birds to act
in so arbitrary a manner, for each would imply an amount of
forethought of which no bird is capable. Must we then regard
the habit as a chance variation, which, having once arisen at
some early stage in the history of bird life, was perpetuated,
owing to its having been of some direct benefit to those species
possessing it? Or is it not possible that it igs linked with
some other mode of behaviour? ‘The latter appears to me to
be the more probable alternative, and it is by no means
unlikely that it has its origin in, or rather is an extension of,
the law of territory. As in so many cases, an interpretation
is rendered the more difficult by the fact that the habit is not
a universal one, but seems to be confined to certain species
only. The Moorhen treats its young, when they are able to
find food for themselves, with scant affection, pursuing and
pecking them unmercifully, and the Stonechat will not allow

20

REED WARBLER

its young to remain in its territory. The instinct is better
known, perhaps, in connection with the birds of prey and the
Raven; and in some cases it seems to be deferred until the
following spring; young Partridges, for example, remain with
their parents throughout the winter. Hitherto, I have not
been able to trace it amongst the Warblers. Whether it is
more prevalent amongst those species that rear two broods, or
whether it is limited to those that remain more or less in one
particular territory throughout the year, we do not know. A
Warbler deserts its territory as soon as the young are reared,
but the Moorhen as a rule continues in the same place during
the winter months. A migratory species would have nothing
to gain by driving away its young, for although it is likely
that both old and young return to the same district the follow-
ing spring, yet it is not probable that the young would lay
claim, even if the parents did so, to the identical territory in
which they were reared. But the case is different with the
Moorhens; they remain in or near their territory throughout
the year, and if they allowed the young to remain with them
it is unquestionable that, as the sexual instinct arose the
following spring, they would have serious rivals in their
offspring, by that time fully developed, and in strength equal
to themselves. There is much evidence to show that in many
cases parental affection is limited to the period in which the
young are helpless, and so the natural result of the law
of territory would be the banishment of the young; and if in
addition the habit was of indirect benefit to a species by pre-
venting interbreeding, or by securing an ample supply of
food, then it would be fostered by selection and developed in
so far as 1t was beneficial.

What, then, is the meaning of this law of territory ?
Why should one male struggle so fiercely with another for
a small plot of ground? It is claimed only at the breeding
season; it is adhered to in many cases only so long as there
is a nest and eggs or young within its limits; it is of such
importance to the individual male that it may even lead to

21

BRITISH WARBLERS

a fatal struggle; and ¢f a territory is won a mate is won also.
No fact has impressed itself upon me more strongly than
this latter, for we know that not all the males, nor all the
females, arrive at the same moment, and so it happens that
one male will commence to breed a week, a fortnight, or
perhaps a month before its neighbour; yet notwithstanding
this difference in time, which, when we take into consideration
how short is the whole period of sexual reproduction, is a very
considerable one, I have not found a single case of a male
securing a territory and not ultimately securing a mate. It
may be urged that the evidence of so small a number of
species is insufficient, but let it be remembered that I have
purposely studied species very widely separated in the phylo-
genetic tree, and have found a similar law in operation; and
if it were not a general rule that territory and reproduction
were synonymous, some instances, some evidence at least,
ought to have come under my notice. It seems evident,
therefore, that a territory is essential to the individual male if it
is to attain to reproduction, and inasmuch as the final appeal
for possession is to the law of battle, we can well understand
that on the average it will be the stronger birds that will
leave offspring to inherit their congenital tendencies; the
weaker will either perish, or which amounts to the same
thing not attain to reproduction. At the same time we
must not always assume that the bird that is defeated is,
although weaker, not so fit to reproduce, or not so likely to
produce healthy offspring, since it is quite conceivable that
up toa certain age the older birds will have an advantage,
due solely to laws of growth, but, on the average, it will
be the stronger individuals that leave offspring. Thus there
is constantly at work each recurring spring a process of
elimination, whereby the species is not only maintained in
a healthy condition, but is gradually being brought to a
greater state of perfection. And so in its immediate results,
the law of territory is nothing more than a form of natural
selection. Before going further, however, it will be necessary to

22

REED WARBLER

state the position with regard to the theory of sexual selection,
for, as I shall presently show, a struggle for territory is not
compatible with one part of that theory.

The theory of sexual selection really contains two
distinct propositions; in the one the male is represented as
attaining to reproduction by conquering other males, while
in the other by directly exciting the pairing impulse of the
female. The first of these is the law of battle, to which is
attributed the greater strength of the male, the development
of the antlers of the stag, or the mane of the lion, since it
is only the better equipped males that will conquer, and thus
be enabled to reproduce and leave descendants similarly
endowed, and differs altogether from the second proposition,
which refers to a peaceable process, whereby it is claimed
that vocal and instrumental music, plumes, and colours in
birds have been developed owing to the fact that the males,
which possess a greater development of those characters
excite the females in a higher degree, and are thus more
likely to attain to reproduction. This second proposition
leaves no scope for the law of battle. Inasmuch, therefore,
as they ignore or regard as of secondary importance the
desperate and frequent struggles in bird life, while at the
same time pleading the immense importance of similar
struggles amongst the mammals, the advocates of sexual
selection are not consistent, for I cannot believe that such
battles have, in the one case, decided the question of reproduc-
tion, but in the other in no way influenced it. Moreover, they
admit that the conflicts at the period of sexual activity are
not confined to mammals, but that they occur amongst the
lower vertebrates, amongst beetles and crustaceans, amongst
some insects, and even amongst some birds. And I therefore
submit that, on their own showing, it is highly improbable that
this scheme by which the male has attained to reproduction,
the standard of efficiency of the species has been maintained,
and the position of the species improved in its relation to
the struggle for existence—a scheme elsewhere so uniform

23

BRITISH WARBLERS

—should have been interrupted in the case of many birds,
butterflies, and certain other insects, and replaced by one
that does not necessarily imply any greater capacity for
resistance on the part of the species in the inevitable struggle.
When we actually see, or even reflect upon, such animals as
stags or lions engaged in mortal combat, we cannot help being
impressed with the grandeur of the scene, and, consequently,
we give to those encounters the attention they deserve. But
the conflicts between small and inconspicuous birds are apt
to escape our attention, and not have an equal share of
importance assigned to them. Yet of the two I know not
whether the conflicts in bird life are not more strenuous
and fierce, do not more often terminate fatally, and have not
in the past exercised a greater influence in their own particular
sphere. After witnessing these frequent struggles in bird life
I confess to feelings of some astonishment that so little regard
has been paid to them as a factor in the evolution of bird life.
It is also stated—and it is an assumption which is necessary
for the theory—that a female shows an active inclination
or disinclination for a particular male. Surely this is not
a very satisfactory explanation, for it shows signs of that
tendency, so fatal to a proper understanding of animal sub-
jective states, to resolve all their activities in terms of human
analogy. But we have already seen that amongst a number
of migratory species not only is there no evidence in favour of
this same predilection, but that there is considerable evidence
against it, for if a male gains a territory it gains a mate; and
there is no reason to suppose that they differ in this respect
from other species, except that by virtue of the fact of the
males arriving before the females we are enabled to arrive at
a more accurate interpretation. And supposing that a
female were really attracted by one male more than by
another, then, in the natural course of events, cases of
possession of territory not leading to reproduction ought to
be of not uncommon occurrence, for so long as it does mean
reproduction, any special individual attractiveness to effect

24

REED WARBLER

the same purpose is unnecessary, or, to state it in another
form, the primary object of the law of territory to the
individual male is to enable it to secure a mate; it is a
form of natural selection in so far as the stronger males
only, on the average, will produce offspring, but this form
of natural selection can in no way account directly for the
development of the colouring of the feathers, vocal powers, or
gorgeous plumes. The primary object of sexual selection to
the individual male is also to enable it, by reason of any
particular attractiveness, to secure a mate, and it thus
attempts to explain the development of those secondary
sexual characters. But there never could have arisen in
Nature, part passu, two wholly dissimilar struggles, both
having the same purpose in view—namely, the attainment
of reproduction by the individual. ‘This, as it seems to me,
is the position with regard to the second proposition of the
theory of sexual selection, and I fail to see how it can by
any means be possible for the one process to work with
advantage side by side with the other. And if it be asked
whether it might not be possible for there to be a further
selection by the females of those males that were victorious
in battle, I should reply as follows: Firstly, that such a
selection would presuppose a large preponderance of males,
which supposition would by no means be justified, especially
when we bear in mind the fact that even the assumption
that males are in the majority rests on no very secure
foundation ; secondly, that, inasmuch as ex hypothesr the
more demonstrative males must always be the stronger, a
law of battle to attain the same end would be superfluous ;
this requires further explanation. ‘That the female prefers one
male before another on account of some special adornment is not
now regarded as probable by those who still hold to the theory
of sexual selection as affording the most reasonable interpreta-
tion of the facts, but that she is unconsciously excited by the one
that is the more demonstrative, and that the demonstration is in
proportion to the strength and consequently to the development

25

BRITISH WARBLERS

of the secondary sexual characters. If this were really true ,
the weaker males would thus be eliminated and an appeal
to the law of battle unnecessary. Thirdly, that it is almost
inconceivable that such terribly severe struggles should have
been developed if they were not of some direct benefit to the
victorious individuals; and, lastly, that in the event of such
a further selection taking place, cases of males possessing
a territory and yet not attaining to reproduction ought, as
already pointed out, to be of not uncommon occurrence. And,
having regard to the very meagre evidence upon which is
founded that part of the sexual selection theory which would
refer the victory to those males that were enabled to excite
the females in the highest degree, and considering, too, the
very strong evidence in favour of the question of reproduction
being decided by a law of battle, it is difficult to resist the
conclusion that the latter is the means by which the weaker
individuals have been debarred from transmitting their defects
to the race.

The fighting of the females, if it can be shown to be charac-
teristic of a number of species, will have an important bearing
on this whole question. In discussing the theory of sexual
selection in the life of the Grasshopper Warbler, I stated as
one of my principal objections to that theory that the ultimate
production of the most healthy and most beautiful offspring
by the selection of certain males is, without a corresponding
selection amongst the females, impossible, and of the existence
of such a selection in any form there is no evidence; and upon
this point I see no reason to alter my views. In fact, further
consideration seems to me to add to rather than detract from
the force of this objection. For it must be borne in mind that
what we are in reality aiming at is the maintenance of the
strength of the species, and in thus stating my objection I
wished to make it clear that in order to attain this end an
elimination of the weaker females is as necessary as an
elimination of the weaker males. Strength and beauty cannot
be separated, and even if it were ultimately proved that there

26

REED WARBLER

were no commingling of the colours as a result of amphimixis
and that, consequently, a dull-coloured female could not
directly influence the colour of the male offspring, yet this
would not affect the issue, for vitality must react upon the
colour and influence the growth of the secondary sexual
characters. Evidence of this can be seen in our domestic
animals, and to some extent even in ourselves. A dog in a
low condition of health loses the brilliancy of the colouring in
its coat, and, as is well known, the colouring of the human
hair is affected by ill-health. But if a law of battle obtains
amongst the females, we need no further explanation as to
how the standard of efficiency has been maintained through
numberless generations.

We have discussed the meaning of a territory to the
individual, and have come to the conclusion that it is the
attainment of reproduction; but inasmuch as this same result
could be gained equally as well without all the complications
introduced by a territory, it is evident that by this means
some larger purpose is being fulfilled. That a breeding terri-
tory is of immense importance we can infer from the fact that
we find the individuals of such widely separated species as the
Falcons, Warblers, and the Moorhen struggling for possession.
For my part I believe that the question of food supply has
been one of the determining factors, although there are two
observable facts which are somewhat opposed to this view.
Firstly, that the members of any one of those species referred
to, while objecting so strongly.to a member of their own
species breeding in their territory, frequently ignore the pres-
ence of one of another species, no matter how closely allied
it may be, and no matter whether it would require a similar
food ; and, secondly, that there are a number of species that
breed in communities. But upon further consideration these
difficulties will be found to disappear to a great extent. It is
true that in Nature we can find more than one species, requir-
ing similar food, inhabiting the same small area of ground.
But supposing the law of territory were temporarily suspended,

27

BRITISH WARBLERS

then there would be nothing to prevent any number of the
Same species congregating within a very restricted area.
Consequently the food supply, which might have been ample
for the progeny of one pair of each of those species, would
become exhausted in the immediate vicinity of the nest. The
parent birds, therefore, instead of seeking and finding food
close at hand, would be compelled to travel further and further
afield, and thus the quick supply of food, so essential to the
welfare of the offspring, would not be forthcoming, and
correspondingly the interval for brooding, which is of such
importance during the early stages of growth, would be
diminished, with results that could only be detrimental, and
in cold wet seasons disastrous to the offspring. Apart
from these general considerations, my belief that the effect
of this law of territory has resulted in securing an efficient
food supply for the offspring in their early stages of growth is
based, in some measure, on the behaviour of certain birds,
both at the commencement of the period of sexual reproduc-
tion and after the young are able to take care of themselves.
If a pool, surrounded by agricultural land and occupied by a
number of Moorhens, is kept under observation early in the
season, it will be noticed that each morning at daybreak the
different individuals will wander over the land in search of
food. Now select some one particular pair, owning a territory,
and notice their behaviour. Any intrusion upon their domain
is resented; it is only necessary for an unpaired individual,
wandering amongst the rushes, to overstep the boundary, to call
forth a peculiar cry from the owner, followed by a determined
attack. Presently one or two individuals or pairs fly or run
out on to the fields to feed, causing a stir amongst the whole
community ; one bird follows another, the pair we are watching
swim towards the shore, join their neighbours, and in company
with them peaceably search for food. The fields are clearly
regarded as neutral ground, the territory itself being probably
not capable, so early in the season, of supplying the owners
with food. But when the young are hatched, the conditions

28

REED WARBLER

are different, aquatic insects being then plentiful, and young
succulent aquatic plants abundant. Or take the case of the
migrants after the young are reared and able to take care of
themselves: the parent birds do not still remain in their terri-
tory, but frequently separate and wander from place to place
with no fixed abode. It cannot therefore be the desire to
secure an efficient supply of food for themselves that causes
the Moorhens to defend their territory so stoutly, since they
seek for and find much of it upon neutral ground. Nor can
it be anxiety to prevent the possibility of lack of food for
themselves that impels the Warblers to struggle together, for
why then should they desert the territory they have won and
so consistently defended as soon as the young reach a certain
age? As I shall presently mention, the Reed Warblers do
seem to regard the tops of the alders surrounding the reed bed
as neutral ground, resorting thereto to seek food for their
offspring. But their territories are small owing to the
comparative scarcity of suitable breeding grounds, and some
relaxation of the general law may be advantageous in their
case.

Glancing at an early period in the history of bird life, we
are now in a position to understand partly what may have
taken place. Those members that were not pugnacious, and
thus allowed others to breed in proximity to them, would
certainly attain to reproduction, but their offspring, if they
did survive, would be weak owing to lack of food and exposure
to changes of temperature, and in their turn would produce a
weakly race unfitted to struggle, when called upon to do so,
with stronger individuals, and so the tendency to sociability,
having in such cases no opportunity for expansion, would
eradually disappear. But the necessity for a supply of food
in the immediate vicinity of the nest would not always have
been imperative, and in some cases might not have been
of sufficient importance to outweigh advantages gained from a
number of individuals congregating together, so that we should
then find members of one species breeding in a community.

29

BRITISH WARBLERS

But with respect to this law of territory we must still regard a
community as one unit, for community fights with community
as one individual fights with another. The Rooks from one
rookery will attack those from another, the members of one
colony of Gannets (Sula bassana) will strugele with those of
another. And it is possible that the attainment of reproduc-
tion may be an even more difficult task for those species that
are sociable, since battles occur between individuals with
respect to their own particular domain even within the pre-
cincts of the territory of a community. At no time are the
Rooks so quarrelsome as when they commence to build their
nests, and though the quarrel may be only caused by one
stealing nesting material from another, yet they certainly
appear to respect one another’s rights. But even the stealing
of twigs and wool would be similar in its results to a battle, if
thereby any particular individual were prevented from breed-
ing. Circumstances compel other species to breed together.
For many sea-birds breeding stations are few and far between ;
nevertheless, even the members of these cliff-breeding species
seem to have their own particular territory; and it must be
remembered that not every Gull nor every Guillemot on a
ledge of rock is a breeding bird. The working of the law of
territory is a beautiful illustration of adaptation, since a
territory is developed in some instances to ensure an ample
supply of food for the helpless young, while in others it is
oradually limited in extent to ensure reproduction, but in
every case perfected so as to hamper in no way, but rather
improve the position of the species in relation to the struggle
for existence. Thus scarcity of breeding stations, scarcity or
abundance of certain types of food, and the relation between
the supply of food and the localities suitable for breeding
purposes must have been taken into consideration as species
arose and adjustments were made accordingly. If the indi-
viduals of any one species were to develop a territory larger
than was necessary, and by so doing prevent a portion of their
own community from breeding, that species would gradually

30

REED WARBLER

be eliminated just as surely as one whose members did not
secure sufficient ground to ensure an ample supply of food for
their young. But it is clearly impossible to trace the history
of the development of the breeding territory unless we have
before us a true phylogeny, and the conditions under which
the earlier types existed. Many of the sea-birds, which breed
upon ledges of rock, are compelled to travel some distance
before they can find a situation suitable for rearing their
offspring, whereas the question of food presents no great diffi-
culty ; consequently the limits of their territory have been
reduced to the minimum size necessary for reproduction. In
a case in which the territory has been developed in order to
ensure an ample food supply during the period of reproduction,

it is possible that the area of that territory, and consequently

the numerical strength of the species, will be found to be
proportionate to the distance its members are accustomed to
travel in search of food. This, in some instances at least,
appears to be the case. Those species that have long dis-
tances to travel are represented by comparatively few, and
conversely those that find food close at hand by numerous
members. The birds of prey wander over a great distance,
consequently their territories are large, and the same may be
said of the Raven. It is not every tree that can supply the
necessary food for the Woodpecker—in fact, such trees are
relatively scarce—therefore it has first to search for and
find the suitable trees, and then it will visit them daily,
generally in routine, covering a considerable area while so
doing. At the same time it by no means exhausts all the
possible food supply; the area covered would possibly be
sufficient to maintain one other pair at least, but by reason
of the fact that the food is difficult to find the distance
traversed may be beyond what is really necessary. In such
a case the conditions of existence might be so strenuous that
it would become of the utmost importance to any particular
individual to prevent, not only members of its own species
but also those of closely allied species, from breeding in the

dl

BRITISH WARBLERS

same territory. This may have been the cause of a struggle
I once witnessed, towards the end of May, between two
Lesser Spotted Woodpeckers (Dendrocopus minor) and one
Great Spotted Woodpecker (Dendrocopus major); the latter
bird defending a decayed tree, in which possibly its nest
was situated, against the onslaughts of the former birds.
I have recently gained some further evidence upon this
point, for I had an opportunity of watching a conflict between
a Great Spotted Woodpecker and a pair of Green Woodpeckers
for the possession of a hole in an oak tree. The struggle
was carried on intermittently for some days, and as far as
actual strength was concerned the Great Spotted Woodpecker
was no match for its rivals, but remarkably persistent, and
although pecked mercilessly whenever, in the absence of the
Green Woodpeckers, it took possession of the hole, yet it
refused to leave the localhty. Struggles between closely allied
species may in reality be of more common occurrence, and may
exercise a greater influence, than is generally supposed ;
amongst the Warblers at least there is no doubt that such
is the case, for Willow Warblers and Chiff-chaffs on the one
hand, and Blackcaps and Garden Warblers on the other, are
constant rivals.

The limits of a territory must be influenced by the
conditions of existence of the species. Swamps overgrown
with the common reed (Arundo phragnutes) not being found
everywhere, the territory of the Reed Warbler is consequently
small, and has, no doubt, been reduced gradually to the
minimum size necessary for the welfare of the species. If the
dimensions had been similar to those of the territory of the
Chiff-chaff, the species would have rapidly disappeared,
Hence there is a point beyond which a species in any one
particular district cannot increase, no matter how favourable
the conditions of existence may otherwise be. Nevertheless
it is probable that this point will seldom be reached, for I can
well imagine that the very fact of territory being of such
importance as to necessitate one male fighting with another

32

REED WARBLER —

for possession would lead to available breeding ground remain-
ing untenanted. For a male when seeking a territory will
settle by chance in a certain place, and finding it already
occupied, will struggle with the owner, and perhaps be
defeated, or quietly pass on. In either case it may lay claim
to adjacent unoccupied land, but it is not unlikely, especially
after a fierce encounter, that it will be only too anxious to
abandon that immediate district, thus leaving available ground
in its rear unoccupied. Every male will not be compelled to
struggle each season for its territory ; it is clearly impossible
that it can be so. On the other hand, if every male has
always equal chances of securing a territory, and thus attain-
ing to reproduction, no elimination can take place and no
beneficial results can accrue to the species. But this will not
be the case; competition will vary in different species, will
vary in different seasons, and even in the same species will
vary in different districts, according to changes of environment
and the rate of increase. The weaker males will often repro-
duce, but, taken over a number of years, the stronger will
reproduce more often than the weaker, and this is all that is
required by the theory.

When we consider all of this, and at the same time bear in
mind that the reproductive instinct is possibly not so strong in
one male as in another, so that in the former case it may
soon become weary of seeking territory and be content to
remain unobserved in a district already tenanted, we can
understand that there must needs be a number of unpaired
birds. The pool in front of my house is generally inhabited
by one pair of Moorhens. One autumn both birds disappeared,
the one some time after the other. The pool then remained
unoccupied until the 16th of the following June, upon which
date a single individual took possession. On July 13th a mate
appeared, and they immediately commenced to build a nest,
ultimately succeeding in rearing a small brood. If territory
were not a necessity, why should these two solitary indi-
viduals of the opposite sex have waited till so late in the

3 33

BRITISH WARBLERS

season before commencing to breed? And is it not suggestive
that breeding operations commenced go soon after the pool
was discovered by the first individual? To Darwin it was
somewhat of a mystery how it came about that within the
same district during the height of the breeding season there
should be so many males and females always ready to repair
the loss of a mated bird, and in the “Descent of Man” he
gives the results of experiments showing to what an amazing
extent new mates will be forthcoming—results which from my
own experience I believe to be in no degree exaggerated—and
he considered that an explanation might be found in the fact
that certain males and females do not succeed at the proper
season in exciting one another’s love, and consequently do not
pair. Which are we then to believe—that males seek the
females, or that the females seek the males? Or must we
assume that a mutual search takes place, the sexes wandering
about on the chance of ultimately discovering a suitable
partner? No one who has studied the habits of the migratory
species can seriously entertain this latter possibility, for
whether the principle of breeding territory be accepted or not,
this fact is patent, that the males settle and remain in a
certain restricted area even before they are paired. Therefore
if one sex does really seek the other, it can only be the females
that seek the males. But since we see, on the one hand, a
proportion of the males settling in their respective territories
and there remaining, and since on the other we know that a
proportion are wanderers with no fixed abode, and find that
the males that remain in one place invariably secure a mate,
while those that are wanderers appear to be always ready to
pair when an opportunity arises, surely a more simple and
more probable explanation of the fact that certain birds
remain unpaired is afforded by the law of territory, the
unpaired males being those which have been unsuccessful in
securing a territory, the unpaired females those which have
been unsuccessful in finding unpaired males in possession of a
home. A curious feature with regard to the unpaired birds is

34

REED WARBLER

that, in the case of many species, they are so seldom in
evidence. But this we can understand if we remember that
such birds would be restless wanderers, not resident in any
one particular locality, but continually being urged to move
from place to place by their sexual instinct; and, if at
any time they should happen to be in or near a territory
already occupied, they would be, no doubt, desirous of
concealing their presence. This fact of the unpaired birds
being so seldom in evidence, while at the same time so
numerous, 18 one of some importance. It emphasises the
close connection that must exist between territory and repro-
duction, for if there is no law of territory how can their
behaviour be explained 2? Why should not the unpaired males
instead of wandering about, apparently wishing to remain
unobserved, be content to stay in one particular locality and
make their presence known by song, as the majority of the
males do who secure mates ?

Many species have extended their breeding range in recent
years and are even now extending it. It may be said that
this extension is not real, but only apparent, owing to the
greater interest taken in Nature by a consequently greater
number of competent observers, so that whereas formerly a
species, although present, remained unobserved, at the present
time if is immediately detected. There is no doubt some
truth in this, but at the same time there is strong evidence
to show that in many cases the breeding range has unques-
tionably been extended. If the extension were limited to
those species only whose numerical strength was exceptionally
great, it would not, perhaps, be quite so surprising. But this
is not the case; even those that are not numerous are slowly
but steadily increasing their range. ‘There is no direct neces-
sity, so far as reproduction is concerned, for a bird to desert
the particular neighbourhood in which it was reared; in fact,
there would seem to be an advantage in its not doing so, since
there would be a greater likelihood of securing a mate in a
district already inhabited by the species; neither is there any

35

BRITISH WARBLERS

reason, so far as we are able to judge, why, in many instances,
more members should not breed in proximity to one another
than actually do so at the present time. Have we not an
explanation in the constant struggle for territory—that
struggle which is such an essential to reproduction, a motive
force, as it were, dispersing the species in every direction ?
But let this, which I have already pointed out, be remem-
bered, that the territories need in no sense be regarded as a
chain with numberless links, and that it is not essential for
every available plot of ground to be occupied before the species
can extend, but that by reason of the strugele being so relent-
less it must happen, and not infrequently, that an individual
will be unnecessarily urged to seek ground beyond the imme-
diate neighbourhood.

Now there is no reason to believe that this struggle for
territory has only recently arisen. Possibly it has been
even more severe in the past. But if proof of its early origin
be required it can be found in this fact, that it is severally
common to and inseparable from the habits of widely separate
species. Therefore let us glance at the past history of an
imaginary species, and, bearing in mind the severity of the
struggle on the one hand, and the long periods of time on the
other, attempt to trace the course of events in so far as they
might have been affected by this law. We must suppose that
the species is of comparatively small numerical strength, and
of limited range, and, further, that a point has been reached
when the individuals that do not allow others to breed in
proximity to them have gained an advantage. Hach recurring
spring the conflict for territory would take place, causing an
extension in the breeding range. In some directions the con-
ditions of existence might be such as would make it impossible
for the species to survive, in others large areas might be
unoccupied, owing possibly to their being passed over un-
heeded, or to the individuals settled therein having been from
one cause or another exterminated and not replaced, and yet
in others the succession of breeding territories might be con-

36

REED WARBLER

tinuous. Thus the range would be gradually extended further
and further from its base until it began to advance into
regions subject to alternations in climate, and in which, con-
sequently, the duration of food supply was more or less limited
to a few months in the year. Whenever this point was
reached, it would be necessary for the individuals to return
for part of the year within the zone of perpetual food supply.
Now we know that, in the case of the migratory species, there
is a strong propensity in the individual to revisit in the follow-
ing breeding season that particular neighbourhood in which it
was reared. But even if we did not know this we should infer
that it was so from our knowledge of the conditions under
which the range of the species is being extended, 7.e., from the
law of territory. For if those males that were forced to desert
a certain district through insufficient food supply during part
of the year did not again go forward the following spring to
their former breeding haunts, overcrowding would occur at
some point; and inasmuch as reproduction would be impos-
sible to a large and increasing number, owing to lack of terri-
tory, the distribution would remain stationary, and a check
would be administered to the welfare of the species. There-
fore any variation in the direction of a tendency to return
would be fostered and developed by selection. And so it
would be with the females ; those that did not return to their
birthplace, or their old breeding haunts, would be less likely to
reproduce, since they would have greater difficulty in finding
an unpaired male in possession of a territory. We can then
understand that the range of our imaginary species would be
extended with a corresponding increase in the distance
traversed by some of its individuals between the zone of
perpetual food supply and the breeding haunts, until the limit
imposed by unfavourable conditions of existence were reached.
And when we consider the conditions under which it must
have existed, the constant struggle and constant search for
new breeding grounds, changes in the earth’s surface, and
changes of climate, resulting in the gradual disappearance of

37

BRITISH WARBLERS

the individuals in some parts of the globe, we can see that it
is more than probable that many districts, formerly inhabited,
would not be inhabited to-day.

In applying this law of battle to the life-history of these
smaller species, I am only extending a principle which is
already recognised as a factor in the evolution of animal life.
But in positing territory as the primary cause of the struggles
I am departing from the prevailing opinion. And inasmuch,
therefore, as this is the point which is the more likely to be.
disputed, it will be as well if we review once more, but
briefly, the evidence upon which it is based, and in so doing
we shall see how impossible it is to reconcile the facts with
the only other possible explanation, namely, that the females,
are the direct cause of the struggles. In the first place, then,
we have this fact established, that in the majority of instances
each individual male of the migratory species when it finally
reaches its destination, and each individual male of the
resident species when the sexual instinct commences to
develop, and in some cases throughout the year, remains
in a certain restricted area encompassed by well-defined
boundaries which it seems unwilling to cross. Next we
have the spectacle of these same males engaging in fierce
conflicts amongst themselves, and in the case of the migra-
tory species even before any females have arrived; and
this one fact, if placed beyond dispute, would alone be
sufficient to show that the females are not the direct
incentive to the struggles. But as the plea of insufficient
observation may here be raised—and no one can deny that
a female skulking in the undergrowth might easily escape
detection—we will pass on to the behaviour of the males
after the females have unquestionably arrived, and we find
them still continuing to struggle after pairing has taken
place, after the nest is built, and even after incubation has
commenced, though with less and less determination as the
season advances; and, moreover, we can observe that these
quarrels follow after, and not infrequently seem to be con-

88

REED WARBLER

sequent upon, one male crossing its boundary and entering
the area of its neighbour. And, lastly, in the case of two
males occupying adjoining territories, one paired and the other
unpaired, we find that the unpaired male frequently attacks
not only the neighbouring male but also the female when
either of them intrudes upon its territory. Any one who
will take the pains to keep under observation two pairs of
Chiff-chafis, or of Blackcaps, living in proximity to one
another, or, better still, some large sheet of water inhabited
by a number of different pairs of Moorhens, can observe for
himself these struggles which are of almost daily occurrence.
And how great an influence they must have exercised upon
the history of any one given species we can well imagine,
when, on the one hand, we remember how incessant they
must in reality be in order that we may so readily observe
them, and, on the other, bear in mind the enormous period
of time through which species have been slowly evolving.

The strength or weakness of the theory lies in the evidence
upon which it is based, that is to say, upon the observation
of one person, and herein, at least, lies a weakness. But
although it is probable that in the details there may be some
exaggeration—and it is doubtful whether the human powers
of observation are capable of always giving an accurate state-
ment of the facts—yet the essential facts I believe to be true;
and I appeal to Nature herself for corroboration. Let these
principal points be borne in mind: that whatever species I
have hitherto studied I have found the question of territory
in some degree present; that the problems with regard to
unpaired birds, rate of increase, extension of breeding range,
and, in the case of the migrants, the hurrying forward of the
males in spring, on this principle become capable of solution,
and once more, and finally, that although the evidence is
drawn from the lives of comparatively few species, yet some
of those species are not closely allied, but belong to widely
separate genera.

39

BRITISH WARBLERS

To return to the Reed Warbler. The females often commence
to arrive shortly after the first males, but how soon after depends
upon whether the arrival of those males was an early one or the
reverse. ‘They are seldom in evidence before the middle of May,
so that if a male arrived at the very commencement of that
month, fully a fortnight might elapse before pairing commenced.
As already mentioned, the period of migration of both sexes
is spread over a considerable time. The female that arrived
on June 21st must still be regarded as a migrant, although it
is quite possible that this particular bird, as also, perhaps,
many of the males that are very late in arriving, was only a
wanderer in this country, not a true migrant in the sense of
having only recently completed its migratory journey. However,
it is quite impossible to decide this; the wandering males may
only be the individuals that have been unsuccessful in securing
a territory, the wandering females those that have been unsuc-
cessful in finding an unmated male in possession of a territory.
The fact of these observations having been made in the centre
of England makes such a contingency more possible than if
they had been made on the south or south-east coast. But
whether it be the case or not, it is evident that solitary males,
forerunners of the migratory movement, are the first to reach
this country, and in this respect the species resembles other
migratory species. The interval between the arrival of the
first male and the first female may vary in different species;
and, if this is so, we should expect it to be of shorter duration
in the case of those species that are accustomed to reach
this country in May than in those that face the cold winds
of March.

The period of sexual activity is disappointing so far as
the attitudes assumed are concerned. There is no abnormal
waving of the wings and spreading of the tail, which is
characteristic of so many species. We may say that the
nervous organisation of the bird is not so highly developed
as that of some others, and thus attempt to account for the
difference, but this does not take us very far towards a

40

REED WARBLER

solution. If we thoroughly understood the development of
the sexual organs and the influences exerted thereby, the
explanation of these activities might be less of a TS)
than it is at the present time.

The unemotional behaviour of the male Reed Warbler at
this period is, then, very striking. He follows the female closely
from place to place as she wanders about his territory, giving
expression to his feelings by occasionally bursting into song,
or by flying at and playing with her, fluttering amongst or
over the tops of the reeds, sometimes even pursuing her
rapidly. In the moments of extreme excitement he sings
rapidly, raising the feathers on his head and back, and loosely
flufing out those on his breast and flanks while doing so.
He also spreads his tail, and slightly raises or rather jerks
his wings. Once only have I seen a male, previous to the
actual construction of the nest, carry, while following his
mate, some material in his bill, and in this instance he
appeared to be carrying some seeds of the bulrush. How
far the duration of the period of sexual activity varies in the
case of different individual pairs I am unable to say. But
it is not very probable that the species differs in this respect
from others. Judging from those instances which I have had
under my notice from the commencement of the breeding
season, this period would seem to be of short duration, for
the nest in one case was actually commenced the very
morning upon which the female arrived. Although the male
sings frequently when following the female, yet his song is
not so persistent as prior to her arrival. The male that had
his headquarters in the salzx bush sang morning after morning
for a whole month until a female arrived, when he almost
deserted the bush and became comparatively silent.

The nest, when built amongst the common reed, is sus-
pended from stems varying in number from three to seven, but
it is sometimes placed in a young alder tree (Alnus glwtinosa)
not more than 5 ft. in height, or even amongst the branches of
willows. But this latter situation seems to be resorted to when

41

BRITISH WARBLERS

the reeds, or rather a territory including reeds, are not avail-
able. When the opportunities of building in the willows fring-
ing the reeds, or in the reeds themselves, are equal, the latter
situation seems to be chosen in preference. I have examined a
number of nests for the purpose of discovering whether, in
their construction, new reeds were made use of more frequently
than old, and whether both new and old were utilised at the
same time ; for it occurred to me that, if the latter were the
case, the growth of the new reeds would cause the nest to
become tilted on one side, and bring about a calamity by
precipitating the young into the water. All three methods,
I find, are followed, although of the nests examined only one
was built upon both old and new reeds; this, however, must
not be regarded as a correct proportion, the number examined
being much too small to enable such a proportion to be
correctly estimated. Asa rule the nest is attached somewhat
loosely to the stems, and it might thus be able to slip and
automatically adjust itself to the growth; but there are budding
leaves on the new stems, and an uneven surface and joints
on the old, which might at any moment prevent its slipping
and result in a gradual tilting of the nest to one side. There-
fore I am inclined to think that the danger is a real one, but
one that is kept in check by selection, and it would in no
way surprise me to find that the number of individuals that
constructed their nests after this fashion was but a small
proportion of the whole. Whether old reeds are used more
frequently than new is difficult to determine, since in many
places the natural conditions have been altered, the reeds
being cut in the winter months and the birds being conse-
quently forced to wait until the new ones have made sufficient
growth before commencing to breed. Neither is it possible
to say, or even to guess, what the original nest-building instinct
of the species was, whether, that is to say, the species as a
whole was limited to the use of new or of old reeds, or whether
some individuals used the one and some the other. ‘The latter
alternative is not impossible, and there may be two races, so

42

REED WARBLER

to speak, one accustomed to construct their nests on old and
the other on new reeds. And, if this be so, it will to some
extent explain the peculiarly erratic arrival of different
individuals even in the same reed bed, the earlier comers
being those which had adapted themselves entirely to the
use of dead reeds. The actual number of stems to which
the nest is woven varies very considerably; one bird will
make use of three reeds, while another of no less than seven.
But the number chosen must have been in the past, and
must be still, so regulated as to ensure the safety of the
young; and in a case of this description we need have little
hesitation in attributing the result to selection. A nest woven
to two reeds, if it were possible to construct it thus, would not
be durable, and even when woven to three does not always
appear to be sufficiently secure, yet this number is sometimes
resorted to; and if three reeds be really sufficient, why, in
so many cases, should four, five, six, or even seven be used ?
It may be suggested that where a small number of stems is
used it is the first attempt of a young bird, and that as it
finds the number insufficient to hold the nest securely, it
profits by experience, and at the next attempt adds another
and yet another stem. But to profit by experience, persistence,
with varying effort, is necessary. ‘ Repetition of trials with
variation of procedure is a sort of perceptual experiment.
The results of previous experiment determine and facilitate
future action, inasmuch as unsuccessful modes of procedure
are gradually eliminated and successful modes alone survive.” *
A bird builds a nest but once a year, and therefore the con-
ditions necessary are not really present in a case of this
description, and to expect it to realise the cause of the failure
of its first attempt, and to overcome its difficulty in advance,
would be to raise the level of its whole behaviour from the
perceptual to the ideational plane, which I do not for one
moment believe we should be justified in doing. And whereas

* Stout’s ‘‘ Manual of Psychology.”’

43

BRITISH WARBLERS

the whole behaviour is so simply explained by selection, in
that those members that did not construct their nest
sufficiently securely would be very liable to loge their off-
spring, we may conclude that this is the means by which
the degree of adaptation has been attained.

The nest is a delicate and beautiful structure composed
principally of the seed-heads of the common reed. The founda-
tion is formed of the leaves, or pieces of the outside of the
stem, of the dead common reed, intermingled with the thinner
stems of various rushes woven together with moss and wool,
and the interior of seed-heads and small stems of rushes, the
lining being entirely of the former. The external part is much
the same as the foundation, wool and moss being interwoven.
The manner in which the nest is actually woven to the stems
is remarkable, and I much regret never having seen the birds
at work “laying the first brick,” so to speak, for to myself
it is a mystery exactly how the initial step is taken. The
most characteristic and at the same time most interesting part
about the nest is its great depth. Such a peculiarity cannot
but be for some purpose, and the reason often advanced is that
the eggs are thereby prevented from rolling out when the reeds
are bent. I have watched the nest swaying in a wind, and
have even bent the reeds for the purpose of finding out how far
it would have to be tilted before this would happen, and the
conclusion thus reached was that even if it were half an inch
shallower the wind would have to be of very exceptional
strength before it could bend the reeds sufficiently to bring
about such a result; for it must not be forgotten that the nest
is not placed at the top of the reeds, but in the centre, three or
four feet from the water. If indeed it be true that there is a
danger of the eges thus rolling out, what must we say as to
the young? Herein, at least, hes a possible danger. Watch
them when a week or ten days old clinging to the nest, the
topmost birds level with or even slightly above the sides of the
nest, and then imagine the nest itself no deeper than that of
the Whitethroat, and the danger will be at once apparent.

44

REED WARBLER

It is remarkable that many, deep as the nest is now, are not
precipitated headlong into the water; but their long legs and
their innate power of clinging, no doubt make their position
more secure than it often really appears to be. The nest is
one of those beautiful adaptations of Nature which justly excite
our wonder and admiration, for on the one hand it must be
sufficiently deep to eliminate all possible risk of the young
being thrown out, while on the other it must not be too deep
to retard the process of incubation. If the depth were too
great, there would be a danger of the young in their early
stages of growth not being sufficiently covered with the feathers.
of the parent bird to ensure their bodies being maintained at
a proper temperature. How important this must be in the
case of the eggs can be readily understood, but it is even more
important—and this can be inferred from the behaviour of the
parents—to maintain the young for the first few days after
they are hatched at a certain temperature. Sleep is to some
extent dependent upon warmth, and sleep is a vital necessity
for the helpless naked young; therefore if the nest were too
deep they would not be properly surrounded with the breast
and belly feathers of the parent birds. Even as it is, the
female when brooding appears to me to be in a most uncom-
fortable position. In the construction of the nest she does
the greater part of the work, carrying billsful of the seed-heads
of the reeds, which she rapidly fixes, and as soon as the outer
part of the nest is completed and it begins to take its proper
form, she lies in it and shapes the interior with her breast by
turning this way and that, and at the same time often uses her
bill to assist In arranging the material in the interior. Her
efforts to build the nest are not without what appears to be
the usual hindrance caused by the exuberant spirits of her
mate, for, while she is at work, he often flies at and pursues
her, with the result that there is much fluttering amongst or
above the tops of the reeds, with an audible clicking of bills
as they meet. Jive or six days may elapse between the time
when the nest is commenced and the laying of the first egg,

45

BRITISH WARBLERS

and as to the period during which the eges are laid the species
does not seem to differ, on the whole, from others closely
allied, one being laid as a rule every twenty-four hours. The
behaviour of the male, directly the first ege is laid, is inte-
resting, aS he at once takes his share in sitting upon and
maintaining it at the proper temperature. Judging from their
actions incubation proper does not commence until the fourth
or fifth egg—according to the number of the clutch—is laid;
for directly the full number is completed their anxiety not
to leave them too long exposed is very apparent. I have
taken particular notice of the behaviour exhibited by the
sexes during the period of incubation, and it does not seem
to me to show any very striking difference. Nineteen minutes
is the longest period I have recorded that the female has
remained upon the eggs, and seventeen minutes in the case
of the male. The one leaves the nest immediately upon the
appearance of the other, and the male will sometimes sing
on the way to the nest, and even while on the nest itself.
The female utters a low quiet note as she approaches and is
desirous of replacing her mate, and whilst sitting upon the
nest pecks at and appears to be arranging the material in
the interior. There is a difference—but whether such differ-
ence is constant, or happens only to have been the case in
those instances I have had under my notice, it is impossible
to say without further investigation—in the direction in which
the sexes face while incubating; each one seems to have its
own particular direction, which it adheres to with more or less
regularity.

Incubation lasts fourteen days, calculating from the day
upon which the last ege of the clutch is laid; and as soon as
the young are hatched the parents become decidedly more
anxious, betraying uneasiness in their movements. Of the
two the male is the more nervous, approaching the nest with
ereat timidity and only with difficulty overcoming his alarm
at one’s presence. But, as already mentioned, the excitement
displayed by the species as a whole, both at this and other

46

REED WARBLER

emotional periods, is as nothing when compared with that of
many others at corresponding periods. I cut away the reeds,
and even make a clear opening of some few feet in length
so as to be able to have the nest in full view, and the female
takes but little notice, hesitating only so long as there is any
appreciable movement, but if I remain motionless for a few
minutes she quietly approaches the nest and attends to the
young. ‘Testing her patience still further, I take up a young
one, hold it in my hand, and remain with it near the nest, but
still she does not respond actively after the manner of the
Blackeap or Whitethroat, travelling only from reed to reed
whilst uttering her quiet purring note. On referring to my
notes taken while watching the nests of various pairs during
the last few years, I have been astonished to find that in no
single instance is there any record of the male brooding the
young. This fact seems so curious that I am almost per-
suaded that it is an oversight on my part; yet the notes seem
to accurately record the actions of the male at the time. It
is the more curious when we remember that he takes his share
in keeping the eggs at the proper temperature before incuba-
tion commences, and that he also shares the duties of incuba-
tion equally with the female. If it is really the case, it is
somewhat difficult to explain, for if competent to incubate,
surely he must be competent to brood, unless there is a
difference in the bodily temperature of the sexes; possibly the
parental instinct is stronger in the female than in the male.
Brooding occupies the greater part of the time of the
female, and is clearly the more important consideration in
the early stages of the growth of the offspring, since warmth
and sleep, the latter dependent upon the former, are then the
necessities of life, food supply being of less importance. But
correspondingly with their growth these conditions become
sradually reversed until food supply is the greater necessity
and warmth of minor importance, a stage which is reached
when their bodies are more or less covered with feathers.
During these few days the male is by no means idle; he is

47

BRITISH WARBLERS

indeed the most persistent of workers, never relaxing his
efforts to procure food, which he delivers to his mate or young.

When they finally leave the nest the young are approxi-
mately eleven days old. During the first few days of their
existence they sleep and receive food, but show little signs of
activity ; about the sixth day their feathers are of a consider-
able length and show the brown colour upon the back. When
about eight days old they stretch themselves, flap their wings,
and peck at the insects on their bodies, and a day later they
are capable of making considerable noise when the parents
bring food, and they also begin to make use of the quiet call
note. On the tenth day they can be seen preening their
feathers, pecking at the insects both upon théir own bodies
and upon the heads of one another. The stronger individuals
now begin to make excursions from the nest, climbing about the
surrounding reeds, only to return shortly, and by the eleventh
day they are all, as a rule, sufficiently grown to be able to
leave.

For the first few days after the young are hatched, brooding
is of great importance, and it is consequently left in a great
measure to the male to collect the necessary food; this he
seeks for the most part in the reeds immediately surrounding
the nest, that is to say, in his own particular territory, hunting
amongst the tops or at the base, which, in the drier parts,
is a fruitful source of supply. Or if in the vicinity of such
trees as alders he resorts thereto in company with members of
his own and other species, for the tops of such trees seem to
be regarded as neutral ground. When he has thus collected
a sufficient quantity of insects he returns to the nest, and
upon his arrival the female raises her body while he places the
food in an open gape; or sometimes he delivers the whole or
part of it to her, and she may then divide it, swallowing part
herself and giving part to the young; or, again, she may pass
the whole of it on to her offspring. So that for the first few
days he is often compelled to find food both for his mate and
young. She, however, does not brood continuously, but leaves

48

REED WARBLER

the nest for short periods, generally returning with her bill full
of insects. About the fourth day the brooding becomes con-
siderably less, and in proportion the supply of food increases,
until both sexes are often at work together collecting and
bringing supplies. The feces, enclosed in a membraneous sac,
are ejected by the young after the food is delivered to them,
and are then carried away or eaten by one or other of the
parents. If defecation does not immediately take place the
parent touches the youngster’s anus with its beak, which
usually has the desired effect.

As it is possible to obtain so clear a view of the nest
and of the behaviour of the parents, I have been much
interested in noticing the method adopted by them when
actually delivering food to their offspring. Where there
are four or five young in a nest we should expect to find
the food delivered more or less in rotation. But this does
not seem to be the case. In fact it may happen that both
parents arrive at the nest simultaneously with food in their
bills, and deliver it into the gape of the same young one,
and also that the same bird is fed over and over again
until—and this will scarcely be credited—it lies with bill open,
apparently too exhausted to swallow so large an amount of
food. At other times the insects are divided more evenly,
three of the young perhaps receiving food from one parent;
and part of it may be even withdrawn from one gape and
placed in another.

The young do not all develop with equal rapidity. The
erowth can easily be watched day by day, and it will be found
that the feathers are more developed on one bird than on
another, and ultimately that one is ready to leave the nest
before the others, and moreover does actually do so, a differ-
ence perhaps of one day, or in some cases even of two days,
intervening. By the expression “leaving the nest” I do not
necessarily mean deserting it, but that the bird is sufficiently
developed to make short excursions amongst the reeds,
returning again to the nursery; nevertheless, cases have come

4 49

BRITISH WARBLERS

under my notice where there appeared to be little doubt that
the young did not all desert the nest at the same moment.
The explanation must be that the stronger individuals, receiv-
ing an unequal proportion of the food, develop more rapidly,
and thus are capable of leaving the nest earlier. But what do
we mean by the stronger individuals? Is it an instance of the
natural selection of those that are more fit? It is a common
saying amongst those who are accustomed to take the young
of such birds as the Magpie (Pica rustica), while still in the
nest, in order to make pets of them, that the females are at
the bottom of the nest, and the males on top. How far this is
correct I have had no means of judging, but it may be a possible
explanation. The males would be naturally the stronger, and
would therefore require and receive a greater supply of food,
and, being the stronger, would struggle until they forced them-
selyes above the females in their efforts to reach the food as it
was from time to time brought by the parents. The explana-
tion of the behaviour of the parents and young may therefore
be this: that the stronger individuals—possibly the males—
require more food and thus are more persistent in stretching
up their necks and opening their gapes. And I believe that
no one could watch a nest of young from day to day without
coming to the conclusion that the most persistent individuals
were the ones that on the average secured a larger quantity of
food, and that this persistency was the direct factor which
influenced the behaviour of the parents; the indirect deter-
mining factor being the relative rapidity of digestion in the
different individuals and the consequent sensation of hunger.
To take an extreme case: a bird that has received a large
supply of food will lie quietly in the nest with a tendency to
sleep, and when the parent again arrives with food and the
remainder of the young stretch out their necks and utter their
call-note, will pay no heed, but will remain in an apparently
sleepy condition. As the process of supplying food continues,
it will gradually rouse itself, at first stretching out its neck
with little determination, but finally becoming frantic in its

50

REED WARBLER

efforts to obtain the food. We may then almost say that the
whole process is a mechanical one; the parents know not,
neither could they possibly recognise that one individual is
stronger and thus would demand more food than another, still
less could they possibly comprehend the difference being a
sexual one, if indeed it were so. ‘Their behaviour is solely
determined by the organic response of the young. It is not
necessary for them to consider—nor do I believe that they
would be capable of doing so—a matter so abstruse as supplying
food in rotation; it is not even necessary for them to remember
to which individual they delivered the last supply of food,
although it is not improbable that they sometimes do so.
After watching the routine of different pairs under similar
conditions, I can see no reason to believe that they in any
way profit by experience. How far their whole behaviour
may be congenital, or how far traditional, it is difficult to say.
We cannot assume that a young male and a young female
never mate together, for if we consider the proportion of young
birds to old, we can see that cases must frequently arise in
which a pair are compelled to build a nest and rear young
antecedent to experience. In some of the cases which I have
from time to time studied, there is a strong probability that
the actors have been performing for the first time; and, if so,
they have taken their part in this complex piece of machinery
as skilfully as the adults. It is true that we could place their
whole behaviour on a level with our own; we could discern
a motive in their supplying one individual more than another
with food, could regard the removal of the feces as an act
of conscious deliberation, could indeed see all their actions in
the highest light possible and thus attribute to them reasoning
powers similar to our own; but of what use would such a
method be? Conclusions thus reached would retard rather
than facilitate our knowledge of their subjective states, and it
might truthfully be said that they would never even enter the
domain of science.

I have in the case of this species also carried out a series

51

BRITISH WARBLERS

of experiments by placing a leaf in the nest in order to see in
what manner the parents would adapt themselves to the
unusual conditions thus presented; whether, as in the case
of the Whitethroat, they would treat it as if it were feces
ejected by the young, or whether they would recognise the
nature of the obstruction. On the whole, there is little differ-
ence between the behaviour of the two species. I have never
seen a Reed Warbler actually swallow a leaf, but its efforts to
do so are equally as pronounced as those of the Whitethroat,
and its failure may be due to physical reasons. The leaf is
picked up and held in the bill, while at the same time the
movements necessary for swallowing are performed; it is
then perhaps dropped, but again picked up and finally carried
away. When a number of leaves are placed in the nest at the
same time, those that slp in between the young and are
pushed to the bottom are allowed to remain. If a leaf of
the same size as the interior of the nest is placed over the
young, thus completely hiding them, the female on her return
takes little notice. There is a shght examination and slight
bewilderment, but nothing more; then she settles down upon
the nest and attempts to brood in the usual manner. How-
ever, the discomfort, and perhaps the feeling that her legs and
feet are not in their proper position and her feathers not
satisfactorily covering her young seem to make her restless,
and in her strugeles to put matters right the leaf is soon
pushed over the edge.

Incidents sometimes occur of so little importance in them-
selves that they may almost seem to savour of triviality, but
whenever they are in the nature of a check to the normal
routine of activities, whenever, that is to say, adaptation to
unusual circumstances is required, then such incidents in
themselves may be said to constitute an experiment, the result
of which is of relatively equal value in enabling us to judge of
the mentality of the actor as the result of an experiment
planned and carried out by the human mind. I can recall
two such incidents, both of which occurred while food was

o2

REED WARBLER:

being carried to the young. It is not an uncommon habit
amongst many species, and it may occur at any moment after
mating has taken place, for the male to feed the female; and
so it happened that while a pair were carrying food to their
young and were within a short distance of one another, the
male clinging to a reed stretched out his neck to the female,
who was also clinging to a reed but facing him, and attempted
to feed her in the usual way. The attitude of the female was
characteristic ; she uttered her quiet subdued note while at
the same time fluttering her wings after the manner of a
young bird. The male also uttered a call-note. Both of
them had their bills full of insects at the time, and it is quite
clear that the female did not require the food, otherwise she
would have swallowed the insects she was carrying; and it
is also clear that if she had opened her bill to receive food
from her mate much of that which she was carrying would
have fallen out.

The second incident was even more trifling. One of the
birds with its bill full of insects attempted to peck at some-
thing which was apparently irritating its leg; this of course it
was unable to do owing to the large number of insects in its
bill, and consequently it seemed completely puzzled, again and
again bending its head forwards, and, while examining its leg,
moving its head as if on the point of pecking, but its mental
capacity did not seem equal to the occasion.

After the young are a few days old, and as they become
more active, they respond more spontaneously to the approach
of their parents. But they do not seem able to distinguish
their own parents from other individuals of the same species.
Even a gentle swaying of the reeds is sometimes sufficient to
cause them to stretch up their necks and open their gapes, so
that in a strong wind when the reeds are blown this way and
that, they seem to be unaware of the approach of a parent
until it is actually on the edge of the nest itself. The noise of
the wind no doubt prevents them from hearing the call-note
which they recognise and respond to.

53

BRITISH WARBLERS

It may be remembered that some of the young are stronger
than others, and that one will. often make a short excursion
into the reed bed a day or so before the nest is finally deserted,
eventually returning. Upon a young wanderer thus returning
I have seen the remaining birds in the nest just as excited and
expectant as if it were a parent arriving with food, stretching
out their necks and not realising the position even when the
wanderer was elbowing its way amongst them. Whether
the young after having deserted the nest return in the evening
to roost I cannot say. For a while they keep close to one
another in the reeds, but they soon become scattered, and
when a reed bed is inhabited by a number of pairs one can
hear the plaintive call-note of the young proceeding from
every direction. At this age they are difficult to find and
difficult to catch, for, though unable to fly, they travel quickly
by hopping from one reed-stem to another. In wet weather,
or when the dew has been exceptionally heavy, which in July
is often the case, their appearance is most pitiable, as their
feathers are bedrageled with the water which collects on the
reeds in such a quantity, especially at the junction of the leaf
to the stem. I once, after some delay owing to the difficulty
in locating the sound, found a young one which could only
haye left the nest very recently, perched upon a large branch
of an alder in such a position that it was impossible to see it
when standing directly underneath. ‘The weather at the time
was wet and the condition of the lttle creature was most
miserable. It had but few feathers on its body and they were
so bedraggled as to be of little use. How, in such a plight, it
climbed so high from the ground it is difficult to understand.
It is probable that the young are more hardy than those of
many other species, for they may be found in a similar con-
dition more or less every morning, and although the feathers
dry very rapidly in the sun, yet it must require an excep-
tionally robust constitution to withstand so constant a
drenching ; possibly many do-succumb to cold and exposure.
How the parents feed their offspring when thus scattered, and

54

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REED WARBLER

whether they are able to distinguish the call-note of their own
from that of other young, it is difficult to say. The same
factor which we discussed earlier no doubt guides them in
regard to feeding in rotation; those that are the more hungry
are possibly the more persistent in uttering their call-note and
do so the more loudly. Owing to the conditions under which
they are born and reared it is probable that there is a very
considerable mortality amongst them, any tendency to weak-
ness being rigorously eliminated. ‘The young of other species
of the same genus are comparatively secure even upon the
eround, and can, indeed, often be found after they have left
the nest hidden amongst the undergrowth. But the young
Reed Warblers must be prepared to take their place in the
struggle for existence immediately they leave the nest; any
weakness that would prevent them from indefinitely clinging
to the reeds until capable of considerable powers of flight
would be fatal and could only result in their destruction; and
to meet this difficulty it probably is the case that they remain
in the nest longer than those of some other closely allied
species, since any tendency to leave it too early would be held
in check. The weakling would neither be able to withstand
the cold, wet weather, nor could it keep up with its parents or
even attract their attention when desirous of food. In fact,
the struggle for existence must, in their case, be exceedingly
severe.

Throughout the whole of June and July periodical out-
bursts of excitement occur amongst the different individuals
inhabiting the reed bed, such outbursts being apparently not
confined to one sex only, although in most instances the
~ males are probably the sole actors. To determine what are
the causes which lead up to these activities is difficult; it is
not even possible to decide whether the participators are in
earnest and the struggles genuine, or whether their behaviour
is an expression of exuberance of energy. Play forms an
important part in the life-history of many mammals. The
rabbit, the hare, or the fox can be seen practising for the

s}9)

BRITISH WARBLERS

more serious side of life, each in its own particular way;
and there is no reason to suppose that this trait is absent
from bird life. But it is by no means probable that the
petty struggles, rapid pursuits, or harsh scoldings, which are
of common occurrence in the life of this species, can all be
referred to this cause, or that they have one and the same
origin. On the one hand we have scolding parties, very
similar to those we find in the life-history of the Sedge
Warbler. As many as six individuals, apparently belonging
to both sexes, collect in a small area, some at the tops of
the reeds and some at the bottom, and produce a considerable
commotion by uttering their harsh scolding note. On the
other we frequently find a number of individuals pursuing
one another, darting in and out of the reeds, momentarily
appearing as they fly above the tops, but rapidly disappearing
again from view, pecking at and fluttering with each other
in the air or amongst the reeds when the unusual shaking
of the stems discloses their exact position; and yet again
we find two or more close together bursting into song and
uttering their notes more hurriedly and more excitedly than
under ordinary conditions.

As already mentioned, the date of arrival of different
individuals varies considerably. The case may be .remem-
bered of the two males which appeared within a few days
of one another; the one secured a mate only upon the day
on which its neighbour’s young were preparing to leave
the nest. Thus it will be seen that in the same reed bed
and at the same time, reproduction may exist in all its
different stages. In one territory a male may be mating,
in another a pair may be busy with incubation, while in
another the young may be on the point of leaving the nest.
So that we have in this fact a possible explanation of much
of the excitable behaviour of different individuals; for the
question of territory is not comparatively absent, as it would
be if the young of all the different pairs were ready to leave
the nest, but, rather, a prominent cause of strife even up to

56

REED WARBLER

the middle of July. This, I think, may often be an ex-
planation of the quarrelling ; but without further observation
it would be unwise to speculate upon the cause of the gather-
ing together of different individuals, of the spontaneous out-
burst of song, and of the pursuits, which possibly are not
in earnest.

Quarrels between this species and Sedge Warblers are not
uncommon, sometimes one being the ageressor, sometimes
the other. They dart at one another with the usual clicking
of bills; and of the two the Reed Warbler seems to be
the stronger. But I have seen a male Sedge Warbler inter-
fere in a most unjustifiable manner. This particular male
owned a territory in some alders adjoining the reeds, and,
as is their wont, favoured one particular tree, from which
he constantly performed the aerial flight and song peculiar
to the species. Now a pair of Reed Warblers were located
some little distance away, and, as if for pure enjoyment, he
would suddenly and rapidy dart at one or other of them, pur-
suing it amongst the reeds and thus causing considerable
commotion. ‘There was no obvious reason for such behaviour,
unless we regard it solely as practice for the more serious
side of its existence, that is to say, the necessary defence,
which might at any moment arise, of its territory.

Few birds sing under smaller provocation. Even a stone
thrown into the reeds is often sufficient, and the advent of a
Jay (Garrulus glandarius), or a Magpie (Pica rustica) will
sometimes produce a spontaneous outburst in which the
majority of the males take part. The spontaneity with which
these outbursts occur is very striking. One, or perhaps two,
males may be leisurely singing, when suddenly, and often for
no apparent reason, all the males burst into their hurried
excitable song for a few moments only, and then again lapse
into silence. ‘The song in which the female occasionally indulges
is peculiar, and differs in this respect from that of all other
members of the genus, excepting the Great Reed Warbler
(Acrocephalus turdoides), that it does not flow evenly from

o7

BRITISH WARBLERS

the throat of the performer, but is uttered in a jerky manner,
giving one the impression of a number of short sentences
with a full-stop at the end of each one, and of considerable
effort in commencing each new sentence. Notwithstanding
this peculiarity, their vocal powers may be said to have
reached a very high degree of development. To my mind
their song possesses an element of cheerfulness, due to some
extent, no doubt, to pleasant associations, and the tone
possesses a peculiar metallic ring which is not present in
a similar degree in the song of other birds with which I
am acquainted. When the males first arrive their song is
persistent, but after incubation has commenced it is not
uttered so frequently, and ultimately it is to a large extent
limited to the spasmodic outbursts referred to. In addition
to the song there are numerous call notes, some of which
are very similar to and difficult to distinguish from those
of the Sedge Warbler. It is possible to distinguish three
distinct calls; the call-note proper used frequently by both
sexes during the mating period, and also when the young are
being attended to; the scolding note peculiar to the assem-
blies; and a harsh note uttered two or three times in succes-
sion, apparently as an expression of anger or annoyance, since
it is usually the forerunner of much fluttering and clicking
of bills. But the most interesting part of their vocal develop-
ment is undoubtedly the power of imitation, which, when
first heard, seems to equal that of the Blackcap or Marsh
Warbler. In reality, however, the bird is not so finished an
imitator as these other two species; for whereas the Blackcap
will produce part or whole of the song of another species in
so perfect a manner as to deceive the human ear, the Reed
Warbler does not seem to be capable of doing so. Its
imitative faculty is generally limited to reproducing the call.
notes and cries of various species inhabiting the same neigh-
bourhood, but some are undoubtedly produced from
memory. I have heard a male, inhabiting some reeds sur-
rounding an inland sheet of water, imitating the cry of the

58

REED WARBLER

Redshank (Totanus calidris). The alarm-note of the Blackbird
is often well imitated, and the call-note of a Pied Wagtail
(Motacilla lugubris) fluttering out of the reeds, or of a King-
fisher (Alcedo ispida) flying above, is sometimes well repro-
duced. The cries of the different Terns, where a colony
happens to be breeding in proximity to a reed bed, will often
be incorporated with the song, and I have also heard perfect
imitations of a call-note of the Blue Tit, Chaffinch, Icterine
Warbler (Hypolais icterina), Sedge Warbler and Willow
Warbler. But in judging of the power of imitation it 1s
necessary to bear in mind the possibility of some of the
notes, which are apparently perfect copies of those of another
species, being in reality a natural part of the vocal powers
of the imitator. For instance, I remember hearing a Blackbird
introduce into its song throughout the breeding season the
cry of the Curlew (Nuwmenius arquata) in a very perfect
manner. Possibly it may have heard a Curlew, but in the
district in which it was singing it is scarcely probable that
it had done so, for that species, with the exception of an
individual occasionally passing over at a considerable height,
is unknown there. At the time I did not believe that the
imitation, perfect as it was, was genuine, but rather part of
the true song slightly altered, and later I was confirmed in
this opinion upon finding that only a slight alteration is
required to produce such a result. There are some imitations
which we need not hesitate to declare to be imitations pure
and simple. When a bird interrupts its true song, and for a few
moments introduces that of another, differing in combination
and possibly in tone, we can point to it with some certainty
as an imitation. On the other hand there may be a perfect
resemblance in the song of two species which we can be
equally certain has no foundation in the imitative faculty.
It is only with difficulty that the true song of the Icterine
Warbler can be distinguished from that of the Marsh Warbler,
yet no one could say that one is an imitation, although it
may be a perfect representation, of the other. Both songs

59

BRITISH WARBLERS

are complete in themselves, and both birds are equally good
imitators of the songs of other species. Between these two
extremes there are a large number of notes uttered by different
species which are very similar, and may or may not be
imitations. I refer more especially to the call-notes, which,
being as a rule single notes, would the more easily be imitated,
and at the same time the more likely to be a natural produc-
tion. But when we consider the extraordinary number of
songs, call-notes, and combinations of sounds, produced by
bird life in general, we ought surely to be astonished, not
that we can occasionally detect a similar note in two different
species, but that we cannot more frequently do so.

In the song of different individuals:there is lttle variation,
nothing in fact to show that it reaches a higher degree of
perfection year by year, excepting perhaps that a greater
number of imitations may be remembered and reproduced.

Their food consists principally of insects, Chirononide
and Limnobude being devoured in large quantities. But
Aplides may be said to form their staple diet, and these
they find clustering on the leaves of the reeds and on the
branches, twigs, and buds of the alders and willows surround-
ing the reed bed. It is always a difficulty to determine
exactly what the insects are which are being taken and
supplied to the young, since their digestive powers act so
rapidly. Even dissection of a young bird immediately after
the parent has supplied it with food is of httle use, the
insects by that time being reduced to a pulp by the diges-
tive fluid, and consequently beyond recognition. ‘This result
is not due to their being supplied with regurgitated food, for
one can see the insects being caught, carried, and delivered
even in a living condition into the throats of the young.
For the purpose of identifying the insects, I have from time
to time made a number of experiments, but hitherto with
-little success. Small pieces of cotton-wool placed in the
throat and secured with a fine thread prevented some of
them from being swallowed, if removed immediately the

60

REED WARBLER

parent had finished its task. But it was by no means
satisfactory, as the wool caused irritation in the throat, and
the young bird consequently made repeated efforts to swallow
it. The insects supplied are as a rule crushed in a lump
by the bill of a parent, but they are not always dead, and
occasionally one will make good its escape when too many
have been placed in the throat at one time.

61

19

MELODIOUS WARBLER.

Hypolais polyglotta, Dresser, Birds of Europe, vol. ii, pl. 80 (adult
male), pp. 517-519, 1874; Saunders, Manual of British Birds,
2nd Kd., pp. 77-78 (woodcut), 1897.

German, Kurzfliigeliger Gartenspotter ; Arabian, Belbél; French, Bec-fin
acterine ; Italian, Canapino ; Portuguese, Folosa ; Spanish, Almendrita de
verano ; Hungarian, Déli fiizike.

DESCRIPTION OF THE PLUMAGE.

Adult Male in Spring.—The upper parts are uniform olive
green washed with a light brownish colour, the rump being
a more distinct olive. The wing and tail-feathers are brown,
the bastard wing, primaries and their coverts, being narrowly
edged with light buff, whereas the median coverts, secondaries
and their coverts, are broadly margined with that colour.
The least wing-coverts are the same colour as the back, and
the tail-feathers are narrowly edged with light buff. The
lores and the distinct superciliary stripe are, like all the
under parts, a bright yellowish colour. Avxillaries and under
wing-coverts are light buffish yellow, the under parts of the
wing and tail lavender brown, and the shafts of the feathers
whitish. The bill is a brownish horn colour, the lower
mandible being buffish yellow at the base, and the mouth
orange red. The iris is dark brown, and the feet horn
brown.

The female resembles the male.

1

BRITISH WARBLERS

Adult in Autumn.—The upper parts are slightly more
greyish buff, and the lower a brighter yellow. The autumn
plumage of the young is similar to that of the adults.

Nestling.—The upper parts are almost buffish grey with
a slight trace of olive, the under parts being ochre yellow.

GEOGRAPHICAL DISTRIBUTION.

This species seems to visit the South Coast only of
England. ‘There are two records from Sussex and one from
Cornwall, but the southern part of Devonshire appears to
have been repeatedly visited. In the remainder of the British
Islands there has been only one occurrence, a specimen
having been obtained at the Old Head Lighthouse, Kinsale,
co. Cork, in September. On the Continent the bird is
principally an inhabitant of the south-western parts. One
specimen has been obtained in Heligoland. Belgium. is
occasionally visited, so is the Valley of Metz in Germany ;
and there is one record from Austria, one from Lenkoran
in Trans-Caucasia, and it has been obtained in the south-
western part of Hungary. In France it does not breed
north of the Seine, but in the centre, west, and south-west
it is generally distributed and common; while in the east
it is found in the provinces of Cote d’Or, Savoie, Haute-
Savoie and Jura. Throughout Spain and Portugal it appears
to be common. In Africa it is plentiful in Algeria and
Tunis, and it inhabits Morocco, the country between Morocco
and the River Senegal, and the Gold Coast Colony; but
in Egypt its occurrence seems doubtful.

In winter it appears to resort principally to South and
West Africa.

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