Transactions
Perthshire Society
of Natural Science

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Transactions of
Perthshire Society
of Natural Science

VOLUME XIII

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Contents

Introduction

Dr I D Sutherland

The Design and Construction of Friarton Bridge

H G Binnie

Botanical Conservation Work at Rotmel Island

A W Robson

The Perth High Street Excavation 1975-77

N Q Bogdan

The Spread of the Great Crested Grebe (Podiceps
cristatus) as a Breeding Species in Perthshire

V M Thom
E D Cameron

The History of Ospreys in Perthshire

M Drummond

Front Cover Illustration by Tom Berthon

Council 1979-80

President

Vice-Presidents

Secretary

Treasurer

Members

James R A i then

James C Angus
W M Scott NDA

Miss R Fothergill MA FSA (Scot)

Kenneth M Mac Alpine MA FRSGS

R But chart C Eng Ml Mech E
Dr J F Mair BSc MB MRCP
Michael Long
Euan Cameron

Dr 1 D Sutherland MD FRCS
R V Crosbee

Ian McLachlan MRCVS DVSM

Alan J fl McKenzie

SDA Dip Agr E A I Agr E

Introduction

In 1887 The Society published Volume I of its Transactions and
proceedings which was offered to Members at the price of one
shilling. Since then the Transactions have appeared at regular, and
sometimes irregular, intervals and at increasing costs. With this
issue we produce Volume XIII with a more modern format and
closer co-operation with the production facilities of Perth Museum.
The papers contributed reflect some of the recent changes in our
environment and natural resources and maintain the scientific
interest and value for which the Society exists. We are grateful to
all our contributors, and appreciate their labours and erudition.

Perhaps the most striking changes in our local environment over
the last few years has been the improvements and remaking of
the main roads in the County, and the bridges over the River Tay.
The Society has been concerned over the damage and loss of some
of the more unusual flora along the river banks. It is good to
record that the Society’s representations in this aspect have
received full and sympathetic appreciation from the Engineers and
Contractors concerned. At Friarton Bridge and Rotmel Island,
higher up the river, construction plans were modified to avoid the
loss of rare plants.

Mr H G Binnie, Resident Engineer at the Friarton Bridge,
delivered a lecture to the Society on The Design and Construction
of Friarton Bridge. This was received with great interest and we
are pleased to be able to publish his lecture. The construction of
the new A9 road beyond Dunkeld required the alteration of the
river course round Rotmel Island. Mr Robson’s paper describes
this and the steps the Botanical Section took to preserve the flora
on the Island. The Botanical Section will be watching the present
construction work on the extension of the A9 to by-pass Pitlochry.

Of great interest to us today, and perhaps of greater value to the
future is Mr Nicholas Bogdan’s contribution in his paper on the
excavations in Perth Fiigh Street during the last two years. Mr

Bogdan was Director of the excavations and among his work force
were members of our Archaeological and Historical Section. This
is a valuable article which will be of significant interest to historians
in the future.

Ornithologists and others will be interested in two papers from
members of the Ornithological Section. Miss Thom and Mr
Cameron contribute a valuable account of the Great Crested Grebe
and its breeding incidence in Perthshire. Mr Maurice Drummond,
who is Warden of the Loch of The Lowes Reserve, brings us up
to date with the return of the Osprey to Perthshire.

The Editor expresses his great appreciation of the guidance and
help he has received from the Director of Perth Museum and his
Staff in compiling this issue of the Transactions. Their interest
and suggestions have been invaluable to one who is inexperienced
in such a task.

Finally, the Society is once again grateful for the skill and expertise
of our Printers without whom this issue could not be produced.

The Editor

The Design and Construction of
Friarton Bridge

H G Binnie

Design

Once the basic decision to build a bridge has been made, a
number of important decisions must follow fairly rapidly. The
first of these is the site of the bridge. The site chosen depends on
a number of different factors. For large bridges, the narrowest
point of any crossing is always chosen to reduce the sheer cost
of the bridge, and all the secondary matters — the approach roads
and existing buildings etc must take second place. For smaller
bridges however, these other secondary points have a significant
effect on the total cost and must therefore be taken into account.
In the case of Friarton Bridge, the factors to be taken into account
were the position of the Craigend Interchange to the south,
Kinnoull Hill cliff immediately to the north of the river, the
position of the Perth to Dundee railway line and, not least, the
Salmon Fishing Bothy at Lairwell. Considering all these points
and the economics of different decisions the final crossing point
was chosen.

Having done this the next step was to decide upon the span of the
bridge, that is whether the river should be cleared in one complete
span or in a number of spans with piers in the river. In order
to consider this decision sensibly it was necessary to look at the
types of vessels using the river. There are a number of small
dredgers which use the river daily and there are also fairly large
cargo vessels which use Perth Harbour. These are fairly common
throughout the year but in September up to 50 in the month use
the Harbour to transport grain to the Low Countries. Generally
the cost of any bridge is directly related to the length of the main
span, the longer the main span the more expensive the bridge.
In this case, however, considering the size of the cargo vessels and
the narrow river it was decided to cross the river in one span to
avoid the possibility of collisions with the piers.

Consideration of the height of the biggest of the cargo ships likely
to use the river determines the required clearance from high water
level to the lowest , point of the bridge over the river.

The site of the bridge, the size of the main span and the height
above the water are thus determined. The loading produced by
heavy vehicles is known, the loading produced by wind etc can be
calculated so that all the information required to design the bridge
has been obtained.

Before the bridge design is finalised many different alternatives
are considered in order to obtain the most economical solution.
Building materials of steel or concrete or a combination of steel
and concrete can be used together with different types of bridges;
an arch or cantilevered bridge or suspension bridge and so on.
Preliminary calculations are carried out using different materials
and based on different types of bridge. Usually from these
preliminary calculations one type of bridge fairly rapidly shows
itself as being the most economic and suitable for any one crossing.
In this case, however, for various reasons, it was not possible to
show clearly that either a steel or concrete bridge would be the
cheapest so two final designs were made, one for a steel bridge,
which in fact is the bridge under construction, and the other for a
concrete bridge. This concrete bridge required more columns, 14
as opposed to the 8 of the steel bridge, and required cable stays

Plan of Perth By-Pass scheme.

to support the river span. This would be done by constructing
towers on top of the river piers and supporting stays from these
towers out to the centre of the span and anchor stays going back
towards the land to balance these loads. As it happened this one
turned out to be some 10% more expensive than the steel bridge
and therefore the steel bridge was adopted for construction.

The steel bridge under construction consists of twin continuous
steel box girders side by side, each girder carries a reinforced
concrete deck and each deck carries one carriageway of the new
road. The girders are 14' 3" wide and 10' deep increasing to 25'
deep over the river piers where the stress is greatest. Each girder
is supported on reinforced concrete columns and these columns
are supported in pairs on large reinforced concrete base slabs.
These slabs are founded on good material where this is near the
surface and on groups of reinforced concrete piles where the good
material is much deeper.

Construction

The construction procedure can be conveniently divided into three
separate stages. Construction of the foundations and the columns;
erection of the steel box girders and construction of the reinforced
concrete deck which forms the roadway proper.

The first operation to be carried out was the excavation for the
foundations of the columns. The ground in the vicinity of the
river is flat and not much higher than the water level in the river
at high tide. This means that when holes are excavated into the
ground they rapidly fill with water to the level of the river making
it necessary to form coffer-dams for the excavations near the river.
These are formed from interlocking steel sheet piles which are
driven into the ground to form a closed rectangle. The earth is
then excavated from within this closed rectangle to form the
excavation for the bases. Once this is done small pumps are
installed and these easily control the water which seeps in and
foundations can then be constructed in the dry.

The bases, which each support a pair of reinforced concrete
columns, are generally 60' x 30' x 10' thick. These were founded
on sound material where this was near the surface, mainly at
each end of the bridge as the ground rises away from the river
but as the columns reach towards the river the good material is
much deeper and piles in these instances were driven through the
soft material. These reinforced concrete piles were driven using
a 4-ton hammer falling through 2' and they were driven through
the ground until they founded on bedrock below. At the first base
to be piled, which was furthest from the river — the piles were

driven about 30' into the ground before they hit rock. At each
base approaching the river the piles became deeper until at the
river pier on the north side of the river the piles went to a depth
of 150' before they hit bedrock.

The number of piles at each foundation depends upon the load
on the columns, at the large river piers which take the biggest
loads there are 120 piles below the base. Each pile is designed
to carry a maximum of 80 tons and to ensure that the piles would
carry this load at least one pile at each foundation was tested to a
load of 120 tons to give a safety factor of 50% on the load. Once
the piles had been driven in and tested then the ends were cut off
to a uniform level and the large base cast on top.

When the bases had been cast then the next operation was to
construct the concrete columns on top. This was done using two
specially made metal formers. These formers were 20' high and
each columm was concreted in a series of 20' lifts. The columns
are approximately 100' high giving five lifts in each column. Each
pair of columns was constructed in tandem and the two shutters
concreted all the columns throughout the job.

Whilst all this work on foundations and columns was in progress
on site, fabrication of the box girders was in progress in the works.
A box girder is simply a rectangular hollow steel tube and the
bridge consists of two of these side by side. Each girder is fixed
to concrete abutments at each end and temperature movements
are allowed for at an expansion joint at approximately the mid¬
point of the bridge and this caters for m.ovements up to 2' 6".
The box girders were fabricated in the works in lengths of approx¬
imately 60' and these were then welded together end to end on
the site to form the continuous girders required in the design.
Each unit was made up in the works completely finished including
three of the five coats of paint. This reduced the work on site
and avoided the expense of erecting on site a semi-permanent
workshop.

The construction of a bridge of this nature nowadays is fairly
straightforward, the use of modern large cranes and heavy lifting
gear making the erection of 60' long, 50 ton box girders relatively
simple. The biggest difficuUy with a steel box girder bridge is the
sheer accuracy required in construction. The bridge consists of
two steel box girders each } mile long constructed from separate
units 60' long. Construction started at each end of the bridge and
the units were lifted into the air and welded together end to end.
Any inaccuracies in any joint would rapidly be magnified as more
units were erected and the accuracy required to ensure that the
completed girders approaching the mid-point from each end
actually met at the correct point in space was very high.

The individual box girder units are built in a series of straights
even though the bridge is curved. The girders could be constructed
on a curve but this would be very expensive and it is not necessary.
The scale of the bridge is such that one cannot see the box girders
are in a series of straights and in any case the concrete deck on
top is built in a smooth curve which disguises the straights below.
In order that the box units fitted together and formed the correct
curve it was necessary to cut the end of each box unit in a
horizontal direction to an accurate angle so that when these units
were welded together end to end, they formed the correct chords
of the correct horizontal circle. If this was not done accurately
then the bridge would not land exactly on the concrete piers and
it would of course completely miss the girder coming to approach
it when it reached the mid-point of the bridge.

Cross-section of bridge construction.

Similarly, box girders were built in an upward vertical curve
between concrete piers. This is because when the concrete deck
is later cast on to the girders, the weight of the concrete causes
the box girders to deflect. If the steel box girders were built
straight between piers then the weight of the concrete would cause
the girder to deflect and sag and although this would not affect
the strength of the bridge it would look unsightly. So the amount
the steel girders would deflect under the weight of the concrete
was calculated and the girder was constructed upwards by this
amount in a vertical curve so that after deflection the correct
profile would be achieved. This vertical curve was made in the
same way as the horizontal curve — the end of each box unit was
cut accurately in the vertical direction so that the box girders,
when welded together end to end, formed the correct chords of
the correct vertical circle.

Also, as the bridge goes round the curve of the roadway the top
of the box girder is super-elevated. This super-elevation changes
around the curve and this also has to be catered for by a further

accurate angle at the end of each box unit. So the ends of each
separate box unit must be cut to a very accurate angle to cater
for horizontal curvature, vertical curvature and super-elevation
producing a complex problem in three dimensional geometry.

Unfortunately, as soon as a girder is erected and a joint welded
a problem arises caused by weld shrinkage. When two pieces of
metal are welded together end to end shrinkage occurs. This
shrinkage can be calculated and in this case was in the region of
i" for each joint. Each box girder unit therefore was constructed
oversize so that after welding, the length of the bridge was
correct. Unfortunately, this shrinkage, which is caused by the very
high temperatures involved in welding, is not always consistant.
So notwithstanding the tremendous accuracy in calculating and
constructing the ends of the box units, errors do arise as soon as
these units are welded. Consequently, after the erection of each
girder unit, it was necessary to do a survey to see in which
direction the box girder was pointing. If excessive shrinkage
occurred on one side of the box girder for example then the whole
box girder was pulled out of line in that direction and it was
necessary to correct this error when erecting the next box girder
unit. So the erection procedure tends to be a constant series of
corrections in order to stay on or as near to the correct line as
possible.

Here another problem arises. Surveys were carried out using
optical surveying instruments — theodolites and so on — but unfor¬
tunately this could not be done during the hours of daylight.
When the sun shines it shines on one side of the steel box girder —
this automatically puts the other side in shadow — and one side
of the box girder is therefore much warmer than the other side
and this side therefore expands more than the other. This
differential expansion causes the box girder to bend in a curve.
We have surveyed box girders on this site on sunny days and
found the end of the girder to be deflected 8" off to one side,
due entirely to the sunshine. So, obviously, it is impossible to do
accurate surveying in this manner and we overcame this problem
by doing surveys at dawn so that the box girder unit had all night
to reach an equilibrium temperature. There was enough daylight
to see by but not enough heat in the sun to cause the box girder to
deviate and true directions could be determined.

In this way, by accurately constructing the box units to start with
and by constantly correcting when errors occurred during erection,
the correct shap© and position for the completed girder was
achieved.

Temperature causes further problems with steel bridges of this size.
The box girders are each } mile long with a joint at mid-way and

9

of course this length of steel expands and contracts a considerable
amount. Any bridge is designed to work within a fixed temperature
range. From the Meteorological Office Records a reasonable
average yearly temperature is determined for the area in which the
bridge will be built and this is used as the basic design temperature.
From the records the highest summer and the lowest winter
temperatures which are likely to be attained in the life of the
bridge are obtained thus giving a working temperature range.
From these temperatures the range of expansion and contraction
the bridge will experience is calculated and everything is designed
to work within these limits.

In the case of Friarton the steel girder is attached to the top of the
concrete columns. As the girder expands or contracts the columns
bend and the maximum movement of this is it 15'' ie 15" each
side of the vertical. The columns are designed to be vertical at the
design temperature and they will bend 15" one way in winter and
15" the other way in summer. The bridge is designed to work in
this manner and once construction is finished then it will work as
designed. However, during construction this is another factor
which has to be taken into account. As the box girders are welded
together end to end temperature is ignored until a pier is
approached. When the box girder unit which will actually land
on a concrete pier is lifted the temperature of the box girder is
measured. The column is standing vertically as no forces are
acting upon it and if the steel box girder is at the design
temperature then all is fine and the box girder can be landed
directly on to the pier. But if the temperature of the girder is not
the design temperature then it is necessary to calculate its expan¬
sion or contraction from the design and then bend over the pier
by that amount. The box girder can then be landed on to the
pier and made fast. When the temperature next reaches the design
temperature the column will become vertical again. It is most
important that this is done correctly so that the columns do act
as they have been designed, that is they are vertical at the design
temperature and they bend one way in winter and the other way in
summer by the prescribed amount.

The erection of the girders of Friarton Bridge was done in two
parts — over the land a large crane, seated on the ground, lifted
up the units and landed them on to temporary props which
supported the weight whilst the welded joints were made. This,
of course, could not be carried out over the river and here special
lifting beams were used. These beams were supported on top of
the partially completed bridge and they, by means of winches,
lifted up completed box units from a barge floating in the water.
The beam lifted up the girder unit and held it until the joint was
welded. Once the jpint was welded then the whole beam moved

forward to the new end of the bridge in order to lift up the next
unit, and in this way the whole of the box units over the river
were erected and welded together.

All the welds were X-rayed in order to ensure that there were not
inherent weaknesses in the welds.

After the box girders had been erected and welded small steel
outriggers were bolted at 10' centres along both sides of each
girder. These were used to support the concrete deck. The main
box girder is the spine of the bridge — on each side are bolted
these small outriggers and over the whole is a reinforced concrete
deck.

The concrete of this deck was formed of lightweight aggregate
made from the residual ash from power stations. This gives a
concrete which is as strong as ordinary concrete but only two-
thirds of the weight. In this way economies can be made in the
construction. If the reinforced concrete deck is lighter then the
steel box girder does not have to support such a weight. Therefore
it can also be lighter and if both the steel girder and the concrete
deck are lighter then the columns need not be so strong and the
foundations need not be so large. This saving in weight of the

View of the completed bridge from the South taken 8.11.78.

concrete deck is reflected throughout the whole structure and does
provide a considerable economy.

The concrete deck is then waterproofed with hand-laid mastic
asphalt which helps to prevent corrosion of the reinforcement in
the concrete deck by prohibiting the ingress of water. On top of
this mastic asphalt are placed kerbs and the roadway running
surface of normal roadway bituminous material. A safety barrier
along the central reserve and a parapet along the outer edge of
each carriageway both of which are designed to withstand impact
loading from highway vehicles complete the structure.

Acknowledgements

The Society wishes to express its acknowledgement to the following
for permission to publish this paper:

The Scottish Development Department

Freeman Fox & Partners, Consultants

The Cleveland Bridge and Engineering Co Ltd, Contractors

D Wilson Laing & Co, Photographers, Blairgowrie

Botanical Conservation Work at
Rotmel Island

A W Robson

The shingle habitats of a fast-flowing river like the Tay, particularly
in its highland reaches, are complex in their substrata and plant
communities, and consequently rich in species. Rivers, being
seasonally varying volumes of water carrying stones, sand, silt and
organic detritus, living and dead, and moving at different velocities
at different times, are restless creators and modifiers of the lowest
levels of valleys initiated during the Ice Ages. The materials they
bear or roll along are deposited when the speed slackens, and
secondarily removed to be re-deposited elsewhere downstream.
Flooding, currents hastening over rapids, the deposition of large
objects such as tree trunks, the exposure of belts of hard rocks etc
all play their part. New channels therefore are constantly being
gouged out as former ones are banked up or become silted back¬
waters. It is this element of continuous change which provides
terrain of scientific value to the botanist. It is not generally
appreciated that it is the natural stratification combined with the
physico-chemical nature of the deposits that determine which
species grow and where they grow. The range may be from single
plants tolerating open, high and dry shingle-banks to those which
fringe the quiet marshy hollows open to the skies or associated with
willow and alder scrub. Deep sand deposits overlying the stony
layers may ultimately carry natural forest, the most advanced of
plant communities. Man has altered the natural picture moderately
in the past and early efforts at containment are seen in the levees
which, where not removed or breached, are still in evidence.

Rotmel Island (Nat Grid Ref 37/003463 OS Map 49) was first
designated an SSSI (Site of Special Scientific Interest) by the Nature
Conservancy in 1955 along with other similar sites on the Tay.
I have endeavoured to illustrate the main motivation for these
conservation measures above.

When the plans for the new A9 Dunkeld By-Pass were intimated
to the Nature Conservancy Council the Assistant Regional Officer,
Dr R A H Smith, notified me, and the Botanical Section thus

became involved in a programme designed to offset potential
damage to the SSSL The topography at this point brought the
projected line of the road well below the existing roadway and close
to where the river’s main channel cut east of the island. Inevitably
a major containment became essential to ensure that the road
foundations would not be undermined. Measures requiring a new
channel to be driven through the island would dramatically modify
the double bend formed by the river’s own forces. In botanical
terms, these would seem to indicate a diminution of the variety of
habitats, a man-controlled re-laying of the shingle and almost
certainly the loss of some interesting species.

Rotmel Island; Position of new A9 and new river channel superimposed
on 1955 map of SSSI indicating former river beds and backwaters at low

and floodwater levels.

From the beginning, co-operation between the NCC and the
Scottish Development Department, the Contractor, and the PSNS
was achieved. It was found possible to conserve intact a small but
typical area of original shingle scrub which could thus act as a
reservoir for natural regeneration of the “landscaped” area when
operations were completed. This undisturbed vegetation was
studied and listed for its constituent species in June 1975. It had
been resolved between the NCC and Derek Lovejoy & Partners,
the Contractors, before the excavation of the new river-bed, to
remove the top shingle and retain it in a heap to be spread out
evenly over the new riverbank, giving at least a chance for any
viable seeds or plant fragments to survive and grow. A programme
of seed collection was undertaken in August and September 1975

at Dowally Island, about a mile upstream, a similar habitat
complex. Seeds selected were mainly of Nootka Lupin, Sea
Campion, Field Mouse-ear Chickweed, but Northern Bedstraw,
Wood Cranesbill, Burnet Saxifrage, Restharrow, and six other
attractive species were included in a mixture. They were held in
dry conditions until, over one and two winters, they could be sown
in appropriate locations. The whole scheme was as carefully
controlled as possible under the circumstances, some seeds being
sown within the conserved area, while the bulldozers were still at
work, and some on the relaid areas after the standard contractual
sowing of Rye-grass and White Clover to “fix” the shingle, the
whole to be allowed to return naturally and gradually to something
resembling the original character of the SSSI.

At the time of writing it must be said that the seasons 1978 and
1979 would have been too early to properly evaluate results. It will
be many years before there is a complete recovery of the desired
character; nevertheless an excursion in 1980 would provide an
informative exercise in assessing the speed of recovery and the
identification of the potential range of habitats which might develop
naturally. The whole co-operative exercise has been immensely
satisfying and demonstrates how, if conservation is built in to
necessary progress of this kind at the outset, change and improve¬
ment may take place without loss of amenity or the extinction of
our heritage of wild flowers, ferns, mosses and lichens or the places
where they can flourish undisturbed.

15

The Perth High Street Excavation
1975-77

Nicholas Bogdan

Since the war, as a result of new building techniques and the use
of plant, the mediaeval deposits of Perth have been increasingly
destroyed during the course of urban redevelopment. In 1968,
perhaps the first rescue excavation to be mounted in a Scottish
burgh was carried out in George Street by the Perthshire Society
of Natural Science (Archaeological and Historical Section). Un¬
fortunately it was not until early 1975 that this was to be followed
up. Then, largely because of increased interest in Perth’s historical
heritage. Miss Thoms of Dundee Museum directed an exploratory
excavation at St Ann’s Lane; substantial amounts of mediaeval
pottery and organic material being recovered, confirming that in
places at least Perth’s mediaeval deposits remained intact to a
remarkable degree. Meanwhile through the work of the Perth
Archaeological Survey (which culminated in the publication in
1975 of an implications report ‘Tt will soon be too late”), it had
become clear that a number of major sites were threatened. It was
also realised that the size of the problem was such that it would
require a full-time archaeological team. The Perth High Street
Excavation Committee was consequently formed in 1975, with a
brief to organise and administer a large-scale excavation on a site
which Marks and Spencer Ltd were about to redevelop on the
High Street.

Originally it was intended that this excavation should last for three
months and be carried out by a team of twenty, but the advent of
the Government’s Job Creation Programme was eventually to allow
the first season to be extended by ten months, and for a second
season of six months. The expansion of the full-time workforce
was commensurate, for it peaked during the spring of 1976 at sixty.
Nevertheless the excavation would not have been extended had it
not been for a delay in the redevelopment plans and the discovery
that this site too was noteworthy for its deeply stratified mediaeval
deposits and anaerobic soil conditions, which were to result in the
recovery of considerable amounts of organic material. At first it

had been expected that it would only be possible to trench parts
of the large site. As things transpired it was possible to open up
much larger areas, albeit only on a scale commensurate with the
complexity of the site and the initial experience of many of the
excavators.

As the demolition of the standing structures was not carried out
until October 1975, it was decided to carry out a detailed architec¬
tural survey for although the buildings mainly dated from the
eighteenth and nineteenth centuries, and were largely in a derelict
condition, it was realised that they, like the archaeological deposits.

formed an important part of Perth’s historical heritage. Almost
immediately the survey revealed that incorporated within the
Masonic Hall, which had been built in the centre of the site in 1818,
were substantial remains of the ‘Old Parliament House’, a typical
example of a late sixteenth century L-plan townhouse. It had
traditionally been associated with a meeting of the Scottish
Parliament, possibly that which met in Perth in 1606. During the
seventeenth century it had belonged to the Conquerors, perhaps the
richest family then in Perth. In 1812, during the demolition of its
south wing, John Duncan, a young chemist who was later to
become famous as a pioneer in the production of anaesthetics,
discovered an early fourteenth century hoard of approximately
fifteen hundred silver coins. Unfortunately he illicitly converted
most into bullion before using the proceeds to further his business
interests. Perhaps surprisingly, during the course of the excavation
only one mediaeval coin, a silver penny of William the Lion
(1165-1214) was recovered. This lack seems to be a feature which
the High Street shares with other urban excavations in Scotland.
There is, however, modern and late mediaeval evidence that barter
was particularly prevalent in Scotland, and it is possible that during
the Middle Ages coins tended to be reserved for foreign trade.
An interesting example of a trade token, decorated on one side
with two stylised confronted ‘peacocks’ was also found. Similar
tokens have been found during recent excavations at Ludgershall
(Wiltshire), London and Dublin; and it has been suggested that
they were intended for circulation by inn-keepers during the period
immediately preceding the introduction of the farthing in England
in 1279. During the second season, a fine example of a balance,
which could, presumably, have been used for weighing coins and
bullion, was discovered.

Although as much as two metres of archaeological deposits had
been destroyed by nineteenth century cellars on both the High
Street and Mill Street frontages, it soon became clear that even
there, between one and two metres remained. On average the
deposits were found to be about 3.5 metres deep, and dated in the
main from cl 140 until the mid-fourteenth century; only in places
did later mediaeval layers survive intact. Even by the standards of
York this seems an exceptionally rapid build up and it seems
probable that during these first centuries a conscious effort was
made to raise the burgh above flood levels. Perth has always been
threatened by floods; in 1209 the bridge and royal castle were
badly damaged, seagoing ships sailed in the streets and the elderly
King of the Scots had to make a hazardous escape with a few
courtiers in a small boat. During the excavation, evidence of
Perth’s seafaring traditions was forthcoming. Apart from the
recovery of iron nails of a type used in ship and boat-building.

18

timbers from a clinker-built boat had been re-used on one of the
structures. In 1621 the recently constructed stone bridge was swept
away with disastrous results on the burgh’s economy for it was not
replaced until 1772; in the intervening period the Tay could only
be crossed by ferry.

Initially it was only possible to excavate in the north sector, but
almost immediately a hitherto unsuspected ditch and robbed-out
town wall (2.5m thick) were detected lying about 23 metres to the
south of the known (but no longer visible) defences. The wall had
been slighted, apparently only a short time after it had been
constructed, and it had been extensively robbed, probably also in
the fourteenth century. In the circumstances, it seems probable
that this wall should be identified with that which Edward I was
building in Perth in 1304. During both Wars of Independence the
English used Perth as a forward supply base as Berwick upon
Tweed, their main base, was too far south. While parts of Berwick’s
Edwardian defences still stand, no trace had hitherto been found of
the wall with which Walter of Hereford, one of Edward’s most
senior master masons, surrounded Perth. Walter had previously
spent a number of years working on the castle and town walls of
Caernarvon.

PERTH HIGH STREET — S\n PLAN

Site plan.

Unlike most Scottish burghs, Perth appears to have had some
defences by the twelfth century. No archaeological evidence of
them was found, and it is probable that all trace had been destroyed
during the construction of this newly-detected wall and ditch. In
January 1313, King Robert (Bruce) personally stormed the town,
massacring a number of the inhabitants and ordering the stone
walls to be slighted. Nevertheless he later visited Perth, and during
the last years of his life leased houses in the town not only for his
doctor but also for his pet lion. In 1 332 the town fell to Edward
Balliol and the ‘Disinherited’ Anglo-Scottish lords, after they had
defeated David Bruce’s supporters at Dupplin. Although Balliol
temporarily re-fortified the town with planks etc it was not until
four years later that Edward III ordered the local monasteries to
pay for the reconstruction of the walls in ashlar. It seems likely
that the robbing of the newly-discovered wall belongs to this period,
and that the original footings were not re-utilised because they were
already being under-cut by the waters of the lade or town ditch.
There was no evidence of a berm.

The wall had cut a number of thirteenth century features, including
a stone-lined pit and an oven, which had partially subsided into
another pit — possibly a well, that had been infilled with a consider¬
able amount of animal hair, probably the waste product of the
local skinners. An adjacent street is still called the Skinnergate,
although during the twelfth century it had been called the Castle-
gate for it then led to the royal castle.

The recovery of more than five thousand leather fragments, many
of them soles, indicates that the site probably included a cobbler’s
workshop. The leather finds also included garment pieces, belts
and straps and a number of knife-sheaths, some of which were
decorated.

Numerous wooden artifacts were found as a result of the excep¬
tional soil conditions. These included an assemblage of turned
wooden bowls and platters, and the staves of a number of bowls,
barrels and buckets. In one place, a large barrel had been re-used
to line a wall. Other notable finds included a well-used mason’s
mall, mallets, spades, a complete ladle, gaming pieces and even
part of a vessel decorated with a face mask. The latter is perhaps
unique, although it is noteworthy that a number of rather similar
ceramic face masks were recovered. Although wooden vessels only
rarely survive, in the Middle Ages they evidently were in everyday
use. Even more exciting was the recovery of part of a stringed
musical instrument — possibly a harp. Musical instruments have
occasionally been found during English excavations, but this was
still a most unusual discovery. During the early Middle Ages, the
Scots were noted as harpists. A particularly pleasing discovery

was a little round box complete with lid. Although it was empty,
it may perhaps have been used as a money-box.

The recovery of parts of about thirty structures was one of the most
important results of the excavation, for unlike England, very little
was known, hitherto, about early burghal buildings. As it is
believed that no existing Scottish townhouse dates from earlier
than the fifteenth century, the evidence recovered from the site was
particularly important, especially for the light it threw on the
relationship between Scottish and English vernacular architecture.
It now seems possible that the two traditions only diverged after,
and possibly as a result of the political and social isolation resulting
from the Wars of Independence. Certainly the structures examined
which mainly dated from the twelfth and thirteenth centuries, were
not unlike contemporary building from south of the Border, which
is perhaps not surprising if one remembers that towns were an
Anglo-Norman introduction into Scotland; Perth being one of the
earliest as well as one of the most important.

The great majority of the structures were post and wattle buildings,
which appear to have been aligned at right angles to the High
Street and by the early thirteenth century extended at least 45
metres back, access to them being provided by a series of gravel
paths. Comparatively little remained of the main structures on the
street frontage. The flimsy ancillary buildings had evidently been
used as workshops, storehouses, byres and stockpens of the type
which can still occasionally be seen in mediaeval illuminated
manuscripts and paintings. Only rarely were internal posts
discovered, and it would seem that the hurdling, and sometimes
planks, served merely as a screen wall against a load-bearing
skeleton frame. Recently traces of similar buildings have been
discovered in Aberdeen, and on the other side of the North Sea in
Lund (Sweden) and Hedeby (W Germany).

From at least the thirteenth century the Scots had close contact
with Scandinavia and the Baltic. In 1297 Wallace wrote to the
Hanse Towns informing them that the Scottish ports were again
open for trade. During the second season a grooved sill-beam of
cl4 metres length was discovered. Although vertical planks had
been socketed into it, it too had belonged to a timber-framed
structure. All that remained externally of one of the more recent
structures, although it probably dated from the second quarter of
the fourteenth century, was the low stone groundwall, which also
would formerly have supported a timber-framed house. Contem¬
porary buildings of this type are known from recent excavations
in Dublin, Winchester, and York; and still occasionally survive
intact in England. Even more surprising was the discovery of part
of the foundations of an early fourteenth century stone house which

had fronted onto High Street. Although no early houses appear to
have survived above ground level in any of the Scottish burghs,
there is documentary evidence for a contemporary stone house in
Aberdeen. The excavation’s historians discovered that Roger de
Ouincy, Earl of Winchester and Constable of Scotland (1195-
1273), had a 'damns lapidea a stone house, in Perth during the
reign of Alexader II (1214-1249). It now seems that stone, or at

Work on the site during the second season. The paving in the top left hand
corner is the level of Bunch’s Vennel, later Parliament Close, dating

from cl 300.

least partially stone, buildings were occasionally built in Scottish
burghs from at least the early thirteenth century, although it was
probably not until the late fifteenth century or even later that they
became common.

Even with the more flimsy structures, a persistent problem had
been subsidence which resulted from the large number of rubbish
pits of various types and sizes that had been dug all over the site.
More than 140 were discovered during the two seasons. So serious
a problem did they pose, that in one place it had become necessary
in cl 150 to lay a 16 metre long section of horizontal hurdling as
a path. Timber pathways are known from the low-lying excava¬
tions in Dublin (Eire) and Novgorod (USSR). During the Middle
Ages wattling had a wide variety of uses. In places, as in Dublin,
it had sometimes been used as flooring, particularly in areas which
were subject to subsidence or undue wear.

It was, however, not only because of the structures that the High
Street excavation was of note. The quantity, richness, and variety
of the finds provided a unique and yet remarkably full picture of
domestic and commercial life in an early Scottish burgh.

Clearly, the site had been occupied by the rich and important for
many of the finds were exceptional; indeed the documentary
evidence indicated that, from the mid fifteenth century at least, the
site had included a number of Provosts and Bailies amongst its
inhabitants. As usual the most numerous finds were sherds of
pottery; over 57,500 were recovered. Most of it had been made
locally, but it did include imported wares from SW France, E
Yorkshire, Flanders, the Rhineland, N France, Germany and SE
England. The detailed study of this, perhaps the largest corpus of
mediaeval pottery so far to be recovered in Scotland, will inevitably
be important for much of it comes from stratified occupation layers
and pits. Most unusually a few of the approximately 3,500 con¬
texts, excavated during the two seasons, can be precisely dated by
resorting to documentary and dendrochronological (tree ring)
evidence. A surprising result of the excavation was the discovery
that the sequence of tree rings of oak from the site was similar to
those from Northern Ireland studied by the Queen’s University of
Belfast; an indication, no doubt, that Perth and Ulster were subject
to similar climatic fluctuations. Further information on the local
climate is likely to be forthcoming from the abundant environ¬
mental evidence from the site. This forms the basis of an
integrated research programme which it is anticipated will result in
a great increase in our knowledge of Perth’s palaeo-habitat.
The botanic evidence is being studied at the University of Glasgow;
while the entomology which may well provide additional informa¬
tion on the use to which different parts of the site were put, is being
studied at the University of York. Research is also being carried

out on the animal hair and bones. The latter, which are nearly as
numerous as the pottery, are already providing most interesting
new evidence on mediaeval dietary preference, animal husbandry,
butchery practice, hunting and the natural environment. A feature
of the site was the particularly large numbers of goat horn cores,
which may indicate the presence of a horner. Rather more unusual
was the recovery of samples of eggshell, including two unbroken
eggs, and even feathers. The excavation of considerable amounts
of animal hair, mainly cattle, were interesting especially as these
can be supplemented by the yarn from the textiles found. Most of
these were wool, although they also included instances of cultivated
silk and goat hair. During the two seasons, approximately 300
samples of textile were discovered; thus forming one of the largest
bodies of material to be excavated in Britain. It is fortunate that
this corpus ranges from fine felted and dyed woollens to coarse
open examples which may have been mats, blankets or something
of this sort. Especially noteworthy was the recovery of three
examples of lacis netting (a form of simple lace), dating from
cl 300. While contemporary examples are known from illuminated
manuscripts and from burials in Burgos (Spain) and Marburg
(W Germany), these from Perth appear to be the first examples to
be excavated in Britain. One appears to be a hair-net while the
others were probably furnishings.

The anaerobic soil conditions preserved a number of worked bone
artifacts, which included examples of both double and single-sided
combs. Perhaps the most remarkable find from the excavation was
one of the bone knife handles; for it had been fashioned to portray
a cloaked figure with leaf decoration around the head. Almost
certainly it represents a ‘Green Man’ or ‘Jack in the Green’, a
folklore figure associated with Spring. The carving of this beautiful,
if rather sinister, piece invites comparison with the finest contem¬
porary stone sculpture. Indeed the ‘Green Man’ motif is occasion¬
ally met with in ecclesiastical architecture. The handle, which had
lost its blade, was found in what was possibly a metal-worker’s
workshop.

Although the site was marshy, nearly 2000 pieces of metalwork
were recovered; much of it in surprisingly good condition. They
included everyday objects such as examples of nails, buckles, barrel
padlocks, keys of various types, shears, scythe and spade blades,
horseshoes and even a curry-comb; a number of knives, some with
their wooden handles still intact, also survived. Items of personal
adornment included brooches, buttons, decorated pins, rings, strap
buckles and even a pair of tweezers. Weapons were also found
including fine examples of a battle-axe, a spearhead, arrowheads of
various types and the handle of a sword. Fragments of chain-mail
also remained. During both seasons a prick spur was recovered;

the earlier, which is of a transitional type that must date from
cl 150, being a fine example of romanesque metalwork. The other
spur dates from cl 300; perhaps appropriately the closest parallel
being the spurs on the tomb effigy of Aymer de Valence, Earl of
Pembroke, who of course took a prominent part in the first War
of Independence. Indeed it was he who surprised and defeated
Bruce at Methven in 1306. The most elaborate pieces of metalwork
recovered were probably two ampullae or holy water flasks which
must have been brought back from pilgrimages; one from Canter¬
bury probably within fifty years of Beckett’s death in 1171. St
Thomas became so popular a saint north of the Border that the
Scots besought his aid as well as that of St Andrew before the
battle of Bannockburn. The other ampulla, which was recovered
during the second season, is shaped like a church, but it has not
yet been possible to determine its source. A pilgrim badge
depicting the crucifixion of St Andrew was also found; it had
presumably been brought back from St Andrews, the metropolitan
church of Scotland.

The ‘Canterbury Ampulla' showing The ‘Second Ampulla’. Although its
the mitred figure of Thomas Beckett. source is not known, it appears to

It probably dates from the late show the coronation of the Virgin
twelfth century, shortly after Mary and may have come from
Beckett’s death in 1171. Walsingham.

One of the rarest types of find were two small ‘purse’ shaped
tokens; one of which was decorated with the Paschal Lamb, a sign
perhaps significantly associated with St John the Baptist, Perth’s
patron saint. During the last century, tokens like these were
recovered from the River Seine; they seem to have been sold as
souvenirs at mediaeval trade fairs.

The ‘St Andrew Pilgrim Badge’. St
Andrews was the metropolitan
church of Scotland and Perth lay
within the diocese of St Andrews.

An overriding impression stemming from the excavation was that
some at least of the early townspeople had been remarkably
cosmopolitan, and yet conversely they had also pursued in some
ways a rural economy in an urban context. Nevertheless the rich¬
ness and variety of the finds did much to confirm that in many
respects Perth had been the de facto capital of Scotland during the
early Middle Ages. Indeed it is interesting to compare it and
Scone’s position and role with that of the City of London and
Westminster in mediaeval England.

Bibliography

Addyman, RV V/ al 1976 Palaeoclimate in urban environmental archae¬
ology at York, England: problems and potential.

World Archaeology 8 (2) 220-233.

Annon 1946 The History of Duncan.

Flockhart and Co, London.

Baillie, MGL and
Pilcher, JR 1976

Climate Records dug from Irish Bogs.
Geographical Magazine 47 (7) 423-6.

Barbour, J 1856

The Brus. Aberdeen.

Barley, MW 1976

Barley, MW (ed) 1977
Barrow, GWS 1976
Brooks, NP 1977

Campbell, J 1899
Duncan, AAM 1974

Forgeais, A 1866
Heighway, CM (ed) 1972
Laing, L 1973

Murray, JC (ed) 1978

National Museum of
Ireland 1976

O Riordain, B 1972

Radley, J 1972

Scone Liber 1843
Simpson, GG (ed) 1972
Simpson, GG (ed) 1974

Stevenson, J (ed) 1841

Stewart, MEC and
Thoms, L 1975

Stuart, J and

Burnett, G 1878

Thompson, MW 1967

Town Defences in England and Wales after 1066_

In Barley, MW (ed), The Plans and Topography
of Mediaeval Towns in England and Wales.

CBA London.

European Towns: their archaeology and early
history. London.

Robert Bruce and the Community of the Realm
of Scotland. Edinburgh.

Urban Archaeology in Scotland.

In Barley, MW (ed), European Towns: their
archaeology and history. London.

Balmerino and its Abbey. Edinburgh/London.

Perth: the first century of the burgh Trans¬
actions of the Perthshire Society of Natural
Science 11, 30-50.

Collection de plombs histoires trouves dans la
Seine. Paris.

The Erosion of History: archaeology and
planning in towns. London.

Cooking-Pots and the Origins of the Scottish
Pottery Industry.

Archaeological Journal 130, 43-56.

Aberdeen: the town beneath the city. Aberdeen.

Viking and Mediaeval Dublin: National
Museum Excavations, 1962-73. Dublin.

Excavations at High Street and Winetavern
Street, Dublin.

Mediaeval Archaeology 15, 73-85.

Economic Aspects of Anglo-Danish York.
Mediaeval Archaeology 15, 37-57.

Liber Ecclesie de Scon. Edinburgh.

Scotland’s Mediaeval Burghs. Edinburgh.

Aberdeen’s Hidden History: a report on
excavations at Broad Street, 1973. Aberdeen.

Documents illustrative of Sir William Wallace,
his Life and Times. Edinburgh.

It will soon be too late. Perth.

The Exchequer Rolls of Scotland. Edinburgh.
Novgorod the Great. London.

The Spread of the Great Crested
Grebe (Podiceps cristatus) as a
Breeding Species in Perthshire

Valerie M Thom
Euan D Cameron

The first recorded breeding of the Great Crested Grebe in Scotland
occurred at Loch of Lowes, Dunkeld, in 1877. Since then the
species has colonised most Scottish counties from Aberdeenshire
and Argyll southwards. In Perthshire, which holds nearly one
third of the Scottish population, it is now found on almost all the
lochs which fulfil its ecological requirements. These appear to be
basically a depth of 10-15 feet or less, in at least part of the
available water area; an adequate food supply, which is almost
certain to be present in a loch of this depth; and reed-beds, or
other suitable cover, for nesting. At the first census of Great
Crested Grebes in 1931, the county population was assessed at
30-32 adults. By 1965, when the census was repeated, the estimated
population — 65-84 adult birds on 20 different waters — had more
than doubled. However, a further census in 1975 showed that
numbers in Perthshire had hardly increased at all over the
intervening ten years.

Breeding records now exist for 26 waters, and birds have been
noted during the breeding season on a further six. These waters
are listed in the Table, together with the date of the first known
breeding and the number of pairs present in 1931, 1965 and 1975.
Nearly half of these lochs are less than 250 feet above sea level,
and most of the remainder lie between 250 and 500 feet. The
highest altitude at which breeding has occurred in Perthshire is at
900 feet on Loch Ordie (where the species no longer occurs), while
two other lochs, Redmyre and Laird’s Loch, are over 700 feet up.
Apparently suitable waters on which grebes have not yet been
recorded, but where they may well appear in the future, include
King’s Myre, White Moss, Loch Voil and Dunalastair.

The 1965 census was carried out largely because relatively high
residues or organochlorine insecticides had been found in Gre"at
Crested Grebes. The census results showed that, contrary to what
might have been expected, the grebe population had increased
substantially in both Scotland and England. It has been suggested

that the increase in England is associated with the creation of
many new reservoirs and gravel pits, but this explanation is not, of
course, applicable to Perthshire.

As mentioned above, the 1975 census indicated that, in Perthshire,
numbers had remained almost static. Four waters occupied in
1965 had been abandoned, but four new ones colonized. It is
interesting to note that the two lochs holding most pairs in 1965 —
Lake of Menteith and Butterstone Loch — had both lost most of
their breeding pairs by 1975, and both have come under increased
pressure from angling and general recreational use; furthermore,
of the four waters colonized between those years. Loch Freuchie,
Butterstone Mill Dam and Glenfarg Reservoir, are less easy of
access to the general public and are also at altitudes of over 500
feet. This indicates that the Perthshire breeding population of
Great Crested Grebes may have stabilized its numbers, but is
having to readjust its distribution to avoid human disturbance
during the breeding season.

Because of worries that the Great Crested Grebes dying as a result
of oil spillage in the Firth of Forth in early 1978 may have been
Scottish breeding birds, the Scottish Ornithologists Club organised
a breeding season survey for this year. The results of this for
Perthshire indicate that local birds were not involved in this
pollution disaster.

Bibliography

Baxter, EV and
Rintoul, LJ 1953

Boase, H 1961

Brown, JA Harvie 1906

Harrison TH and
Hollom, PAD 1932
& 1933

McMillan, RL 1975

Prestt, I and

Mills, DH 1966

The Birds of Scotland.

Birds of North and East Perthshire.

A Vertebrate Fauna of the Tay Basin and
Strathmore.

British Birds 26, 62, 102, 142, 174 & 286.

Unpublished.

Bird Study 13, 163.

Perthshire Lochs for which Records of Breeding
Great Crested Grebes exist

First

recorded Number of pairs present

Loch

breeding

1931

1965

1975

Lowes

1877

nil

4

5

Menteith

1896

1

7

3

Dupplin

1903

2

3

4

Clunie

1904

1

3

5

Drummond

pre-1905

no data

1

1

Watston

1906

no data

1

nil

Butterstone

1910

nil

5 +

1

Ochtertyre

C1911

1

1

nil

Craiglush

pre-1912

nil

2

2

Redmyre

1912

nil

One bird

nil

Marlee

1912

2

2

1

Lubnaig

1912

1

nil

no data

Ordie

1920

no data

nil

no data

Doine

1927

no data

nil

no data

Methven

1931

1

nil

no data

Rae

1931

1

1

one bird

Stormont

1931

2-3

1

8

Rusky

1931

1

nil

no data

Balloch

1965

1

1

Fingask

1965

1

nil

Stare Dam

1965

1

2

Laird’s Loch

1965

1

nil

White Loch

Blairgowrie

1975

1

Freuchie

1975

1

Butterstone Mill Dam

1975

1

Glenfarg Reservoir

1975

1

Summering, but no breeding records, also exist for Monk Myre, Mahaick,
Carsebreck, Seamaw, Old England, Glack and Abercairney.

30

The History of Ospreys in Perthshire

Maurice Drummond

There is no doubt that in past times Ospreys were present and
breeding in Scotland in abundance. Reliable and accurate records
of their presence and breeding sites are few until last century. By
that time the Highland Clearances had changed the use of the
countryside and led to the formation of large ‘sporting’ estates and
extensive sheep farming. Ospreys were shot as a sporting achieve¬
ment and their nests were systematically robbed of their eggs by
collectors. The result was the extermination of the Osprey in
Scotland by the end of last century.

Macgillivray writing in his History of British Birds in 1840 says
that Loch Tay was ‘a residence of the Osprey’. Jardine in 1841
says the Osprey used to breed on the Isle of Inchmahone in the
Lake of Menteith until scared by repeated plunder of their nests
they deserted the Lake. Harvie-Brown writing in 1906 says the
Osprey was known to breed in the Rannoch area. The same writer
records that a pair of Ospreys attempted to breed on Loch Ordie
in 1886 but the female was shot, and in 1887 another was shot in
that area.

The Loch Ordie Ospreys were both shot by an Atholl gamekeeper.
The 1887 bird was stuffed and is in Blair Castle. The eyrie was
taken down and given to Perth Museum, where it can still be seen.
One of the men who helped to cut down the eyrie was a young
forester who later became an Atholl gamekeeper whose beat
covered Butterstone and Craiglush and the Loch of the Lowes.
It was in the late 1960’s that Ospreys began to appear again over
these Lochs. This is ideal Osprey country with shallow lochs
containing pike and perch, and suitable Scots pine trees for nesting,
with dead pines near by for perching on.

In the first week in April 1969 a male Osprey appeared, a month
after the Loch of the Lowes had become a reserve of the Scottish
Wildlife Trust. He was joined in early May by a female, and
during that summer they built an eyrie on a slender 90 feet pine

tree at the west end of the Loch. The nesting tree swung in the
wind and it was feared that the eyrie could easily fall or the eggs
roll out of the nest. To prevent this the tree was secured with four
guy-ropes in the early spring of 1970. The birds returned in April
1970 and laid two eggs. In spite of the guy-ropes one end of the
eyrie was blown down in a gale and the eggs were lost. That pair
of Ospreys built only one ‘frustration’ eyrie during the summer, on
a much more sturdy pine tree at the south-west corner of Craiglush
Loch.

In the following Spring, before the return of the Ospreys in 1971,
a device was erected to foil egg collectors. This was a steel collar
round the tree some 18 feet from the ground. From this collar
were attached five downward sloping five feet long steel bars,
interlaced with barbed wire. The Ospreys returned that year and
successfully bred two young. In 1972 the birds again returned to
the same eyrie and there was another successful breeding.

In 1973 a female Osprey arrived first and instead of using the eyrie
of previous years she carried sticks and began to build a new nest
on a small Pine between Craiglush Loch and the Loch of The
Lowes. She was joined by a male. Again eggs were laid and
successfully hatched. A pair of Ospreys hatched two young in the
same eyrie in 1974. In 1975 a pair of Ospreys were present
throughout the summer but did not breed. The weather in April
and May was very cold. The birds were in poor condition and
showed no interest in nest building until August when they carried
sticks to the eyrie.

In the first week of April 1976 two Ospreys arrived and began
repairing the eyrie. The male was an unusually shy bird, and as a
result of being disturbed by a man with sheep among the trees at
the west end of the loch, he disappeared. Another male took over
and was joined by a second female. For the next eight weeks there
were two females and one male at the site. The females took turns
at incubating and often sat side by side on the eyrie. The male
would bring in a fish, give it to one of the females who would then
feed the incubating female. It was expected that the eggs would
be infertile as no mating appeared to have taken place. The birds
left the eyrie after seven weeks of trying to incubate the eggs. Two
days later the nest was inspected and no eggs found. They had
probably been taken by crows. The birds disappeared in July and
did not build frustration eyries in the Loch of the Lowes area.

In 1977 there was another very cold Spring. Although birds were
present in the area and often seen, no nesting occurred.

In 1978 the first bird did not arrive until 19 April. The eyrie was
rebuilt and the female was seen to be carrying moss to it. It looked

as if she was going to lay but on 7 May she disappeared. It is not
known what happened to her. On 2 June a new pair of birds
arrived and remained until 6 September carrying sticks to the eyrie.

In 1979 the same pair of birds arrived and the eyrie was rebuilt by
the end of April. The female was a young bird and did not lay
eggs until 12 May. Two young Ospreys were successfully hatched.
All the previous Loch of the Lowes young birds flew for the first
time 52 days after hatching. The 1979 birds first flew together on
the 57th day from hatching and did not leave for Africa until
20 September. They were ringed before they left.

The Loch of the Lowes Ospreys are looked after by the Perthshire
Branch of the Scottish Wildlife Trust, assisted by members of the
Perthshire Society of Natural Science who act as part-time
Voluntary Wardens. During the nesting and incubating period the
tree is guarded 24 hours a day. The young birds are ringed with
the assistance of the Highland Officer of the Royal Society for the
Protection of Birds, whose advice is available on problems of
management that may arise. In 1979 some 20 breeding pairs of
Ospreys were recorded in Scotland, but for the protection of the
birds the only sites publicised are the Loch of the Lowes and Loch
Garten in Inverness-shire. The Osprey is now a protected bird in
this country but its eggs are still sought by unscrupulous collectors
for flnancial gain, hence the need for secrecy of the nesting sites.
The Scottish Wildlife Trust’s observation hide at the Loch of the
Lowes allows a clear view of the present and past eyries. It was
built in 1970 and since then 400,000 visitors have visited the hide
and the Visitors’ Centre, most of them to see the Ospreys.

Design & Layout Robert Jarvie

Munro & Scott. Ltd., Skinnergate Printing Works, Perth