Hi Tweets,

>Here are the results for the January Raptor Count, organized by the
>Vancouver Natural History Society and the Burke Mountain Naturalists.

I took the liberty of collating the Raptor Count (Vancouver BC) results 'cos
I was curious to see what they looked like. Here's the results. Totals
first, then by species, then a few thoughts.

TOTALS

Total Areas: 17
Surveyed: 12
Non-surveyed: 5
Coverage: 71% (70.588%)

Total Raptorial Sp.: 13
Total Individuals: 419

Total Adults: 212 (51% of total)
Total Immatures: 58 (14% of total)
Total Unaged/Unsexed: 149 (36% of total)

Bald Eagle 233 (56% of total)
Northern Harrier 48 (11%)
Sharp-shinned Hawk 2 (0.5%)
Cooper's Hawk 5 (1%)
Red-tailed Hawk 96 (23%)
Rough-legged Hawk 14 (3%)
Merlin 5 (1%)
Peregrine Falcon 4 (1%)
Barn Owl 2 (0.5%)
Great Horned Owl 2 (0.5%)
Long-eared Owl 3 (0.7%)
Short-eared Owl 3 (0.7%)
Northern Saw-whet Owl 1 (0.2%)

Diurnal Raptor %, by type:

Eagle: 56%
Harrier: 11%
Accipiter: 7%
Buzzard: 26%
Falcon: 2%
Owl: 0.7%


BY SPECIES

Bald Eagle (BAEA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
157 23 233

Northern Harrier (NOHA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
6 11 31 48

Sharp-shinned Hawk (SSHA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
2 2

Cooper's Hawk (COHA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
2 3 5

Red-tailed Hawk (RTHA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
31 2 62 96

Rough-legged Hawk (RLHA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
1 1 3 9 14

Buteo sp.
Ad. Imm. Unaged/Unsexed Total
M F U M F U
1 1

Merlin (MERL):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
1 4 5

Peregrine Falcon (PEFA):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
1 3 4

Barn Owl (BNOW):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
2 2

Great Horned Owl (GHOW):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
2 2

Long-eared Owl (LEOW):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
3 3

Short-eared Owl (SEOW):
Ad. Imm. Unaged/Unsexed Total
M F U M F U
3 3

Northern Saw-whet Owl (NSWO):
Ad. Imm. Unaged/Unsexed Total
M F U M F U


COMMENT
1 1
What to make of this? First thought: Rough-legged Hawks may be in trouble in
Vancouver BC--that seems quite a small number for the areas surveyed and may
show the influence of the changes in agricultural uses of the land: more
huge greenhouses, less rough pasture lands.

Likewise, that's a *very* low total for Short-eared Owls in the surveyed
areas. There's a number of possible explanations: with all the rain lately,
the fields have been flooded, driving the Townsend's voles to the surface,
making them dead easy to catch; maybe the owls are fuelling up early and
spending most of the day out of sight in ground roosts. Another possibility
is that the Boundary Bay foreshore ground roosts are disturbed by people
running their dogs offleash, or other human disturbance, and they've gone
elsewhere, as they will abandon an area if so hassled, as Iona/Sea Island's
once-substantial but now virtually vanished population has demonstrated.

Might be worthwhile to compare the above with previous CBC totals over the
last thirty years (1968-1998) or so (pre-development totals for the
baseline, and then graph out the differences as the areas become built up to
the present) for the areas; that is, to total all the raptor numbers for all
four or five of the Lower Mainland CBC's each year to see what the total
Lower Mainland CBC count is. Then you'd have a handle on how human habitat
change and destruction has actually effected these species.

As for whether these are typical ratios between the various types of
raptors, I don't know. Typical for the month? The area? Are these
percentages found elsewhere, such as Skagit Flats?

Well, there's a start.

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)