Bird of the Month:
Tracking tip: Look closer
| David Brown's Wildlife Services 12 Hotel Road Warwick, MA 01378 Tel 978 544 8175 E-mail: info@dbwildlife.com |
| Encounters |
| "Tracking is seeing. Seeing is done with the mind." |
Tracking problem:
Eastern bluebird
A confusing background often
obscures animal evidence. This
scraping occurred on the shore of
Quabbin Reservoir and appears at
first glance to be so chaotic as to yield
little evidence of the scraper. But look
a little more closely. Spoil from a dig or
scrape often holds the last footprint
the animal made just before departure.
At the center bottom is the signature of
the artist, the front print of a river otter.
These aquatic mammals often come
ashore for a little "clamming" after
fresh water mussels. Care must be
taken to distinguish otter work from
that of raccoons, however, which
can make superficially similar prints.
obscures animal evidence. This
scraping occurred on the shore of
Quabbin Reservoir and appears at
first glance to be so chaotic as to yield
little evidence of the scraper. But look
a little more closely. Spoil from a dig or
scrape often holds the last footprint
the animal made just before departure.
At the center bottom is the signature of
the artist, the front print of a river otter.
These aquatic mammals often come
ashore for a little "clamming" after
fresh water mussels. Care must be
taken to distinguish otter work from
that of raccoons, however, which
can make superficially similar prints.
Perhaps everyone's favorite bird, even those who have
never seen one, the eastern bluebird's soft warble
reminds us that it is a member of the thrush family, as is
the American robin. Its preferred habitat is fields around
the edges of which it perches on tree branches, telephone
wires or fence posts as here, inspecting the grass below
with its acute eyesight for the slightest movement of worm
or larva. Its luminous cobalt blue back and head seem
almost impossibly vivid to the human eye..
Bluebird populations suffered badly from loss of habitat
due to the decline of agriculture in New England in the
20th Century. A gentle, unaggressive bird, it is easily
out-competed for cavity nest sites by two exotic invaders:
the house sparrow and the European starling. Its numbers
have partly recovered due to the efforts of many admirers
who have erected bluebird boxes in mowed fields and golf
courses. A certain ruthlessness is required by these
well-meaning hosts, however, who must not only clean out
the boxes before spring arrival but also destroy the nests
of any house sparrows or starlings that may take over the
boxes. Failing to do so adds to the problem rather than
solving it.
never seen one, the eastern bluebird's soft warble
reminds us that it is a member of the thrush family, as is
the American robin. Its preferred habitat is fields around
the edges of which it perches on tree branches, telephone
wires or fence posts as here, inspecting the grass below
with its acute eyesight for the slightest movement of worm
or larva. Its luminous cobalt blue back and head seem
almost impossibly vivid to the human eye..
Bluebird populations suffered badly from loss of habitat
due to the decline of agriculture in New England in the
20th Century. A gentle, unaggressive bird, it is easily
out-competed for cavity nest sites by two exotic invaders:
the house sparrow and the European starling. Its numbers
have partly recovered due to the efforts of many admirers
who have erected bluebird boxes in mowed fields and golf
courses. A certain ruthlessness is required by these
well-meaning hosts, however, who must not only clean out
the boxes before spring arrival but also destroy the nests
of any house sparrows or starlings that may take over the
boxes. Failing to do so adds to the problem rather than
solving it.
This photograph was taken in the Red
Rocks country of north-central Arizona, but
it could well be in New England in any
sandy substrate. In the deeper indentations
the soil granules have migrated downward
with time to the "angle of repose", softening
the print definition. However, the shallower
portions have retained fairly sharp edges.
1. Which is the front print and which the
hind? How do you know?
2. Identify the mammal. (Carefully analyze
what shows and what doesn't. Take into
account the distortions of time and the
relative shapes of the two prints.)
3. Determine the gait (There was a line of
similar patterns about 16" apart.
4. Determine the speed: fast, medium, slow.
5. The trail of prints was along a hiking trail.
Given the gait and location, was the animal
travel-hunting, pursuing, escaping?
The solution is elsewhere on this site.
Rocks country of north-central Arizona, but
it could well be in New England in any
sandy substrate. In the deeper indentations
the soil granules have migrated downward
with time to the "angle of repose", softening
the print definition. However, the shallower
portions have retained fairly sharp edges.
1. Which is the front print and which the
hind? How do you know?
2. Identify the mammal. (Carefully analyze
what shows and what doesn't. Take into
account the distortions of time and the
relative shapes of the two prints.)
3. Determine the gait (There was a line of
similar patterns about 16" apart.
4. Determine the speed: fast, medium, slow.
5. The trail of prints was along a hiking trail.
Given the gait and location, was the animal
travel-hunting, pursuing, escaping?
The solution is elsewhere on this site.