Tuesday, October 27, 2015

Holiday Beach Raptor Counts Oct 2015 vs Oct 1975

If you go to HBMO's website, they have a feature where you can look at monthly counts for any year that they have been counting. If you compare this October's monthly total with say, Oct 1975... How have things changed?


Species Oct-15 Oct-75
Turkey Vulture 48066 319
Osprey 15 3
Bald Eagle 64 0
Northern Harrier 335 44
Sharp-shinned Hawk 3208 1546
Cooper's Hawk 129 20
Northern Goshawk 2 1
Red-shouldered Hawk 223 45
Broad-winged Hawk 152 257
Red-tailed Hawk 632 1575
Rough-legged Hawk 0 10
Golden Eagle 18 5
American Kestrel 422 216
Merlin 21 1
Peregrine Falcon 24 0

It seems that raptor numbers have increased for most species. For example, Bald Eagles, and Peregrine Falcons are both pretty easily seen now that DDT was banned. I'm surprised to see that Red -shouldered Hawks have increased. I was under the impression they were decreasing in numbers along with forest habitat. Turkey Vulture counts are just off the charts! This October, 48,000 - but back in Oct 1975 319 were seen! 

To be fair when looking at the data, back in '75 they have 91 hours of observation, and this year, there was 223 hours of observation.

Its interesting to ponder what has tipped the scales for Turkey Vultures? Has the creation of more roads, created more roadkill, and more carrion diet for the species? Has our garbage both at landfills and campgrounds helped this species out in an exorbitant fashion?

I was interested to see what the numbers above would look like in a chart, so I created a quick vertical bar chart in Excel. One chart includes Turkey Vultures (distorting the scale for the other less numerous raptors) and one without Turkey Vultures to get a better look at the lower numbered raptor trends. If turkey vulture counts continue to increase, perhaps a logrithmic scale would be better to use when graphing monthly totals.

It seems that this week, Mars,  Venus & Jupiter can be seen all in close proximity before sunrise. I might try to see it tomorrow... If its not too cloudy!

Good birding,

1 comment:

  1. Hi Dwayne---Good luck with the planet watching--I studied their positions a week or so ago, to have a better perspective of the changes--that works--
    But since that time, the sky has been too cloudy to see
    all 3 at once. Yesterday, early morn, I saw 2 of the three. I assumed they were Venus and Jupiter--but
    couldn't be certain of the least brightest. Anxious to
    see all 3 as they cross paths. We have a few more
    early mornings to witness it. I find the best time is well
    before sunrise--even tho' sources say "just before ".
    With the time change this week-end, it will be even
    earlier. p.s. In the "Bird" news---I now share the glory
    of having 100's [ actually 1000's ] of Crows in my backyard trees every night ! Really---they talk all night long ! Very sociable creatures--but not loveable !



Related Posts Plugin for WordPress, Blogger...