
КОНТРОЛЬНІ ЗАВДАННЯ
- 136 -
Weather is probably the single most important factor in the improvement in
the heron population. In effect, new areas of habitat have been opened up
_________________4_____. The one of 1963 had a notable impact, but
surprisingly there is little to suggest that the same happened in the freezing
temperatures of 1979 and 1892.
____________________5_______ As well as the UK, similar increases
have been recorded throughout Europe. By the early 1970s, the heron had
become threatened in many parts of central Europe, but has since recovered
dramatically. And if not persecuted, will even breed in city centres, such as
happens in Amsterdam.
__________6________ There are still numerous threats, mostly to do with
habitat degradation, and which certainly affect populations on a local scale.
Drainage of fields and excavation reduce food supplies. The planting of forests,
while providing nesting sites, may also reduce the water flow in some water
courses and hence fish availability.
The heron lives on fish. __________7___________. On other occasions a
different tactic is adopted, this time slowly stalking through the water, looking
intently at any stirrings. If the need arises, the heron will wade deep until the
body is afloat and it can even swim for a short distance. They are such a delight
to watch, particularly in the morning when they go hunting in the frost-draped
winter semi-darkness.
a) Another reason for this increase can be found in the milder winters and
the reduction in water pollution.
b) Further north the bird is equally widespread, although it is absent from
areas of high ground.
c) Such nervousness is understandable, given that they have suffered from
persecution from fish farmers.
d) While heron numbers have increased, it is important not to be
complacent.
e) However, a hard winter will temporarily set numbers back.
f) The commonest hunting technique is to stand still by the water's edge,
with only the eyes twinkling as it carefully scans for fish.
j) It appears, however, that all is well for the heron at the moment.
k) But once dawn broke, the herons would move upstream to quieter
stretches of the river.