|
|
|
|
SITE NAME
|
|
Kuparuk and Prudhoe Bay oil fields, USA
|
|
| Contact details
(phone/fax//e-mail//address): |
| + 585 256 0842/+ 585 256 0842(fax) // jokli@FRONTIERNET.NET // 410 Linden St, Rochester, NY 14620-2442, USA
|
|
PROJECT DETAILS |
|
Project name:
|
|
Foraging Ecology of Common Raven
|
|
|
Start of survey:
|
End
of survey: |
Team
size: |
|
21.04
|
28.07
|
3
|
|
WEATHER
CONDITIONS
|
| Season phenology: |
average
|
|
|
Weather conditions: |
| April and May were warmer than average, followed by cooler June and July, thus the onset of the season and advance of vegetation was late and slow. The season was markedly cooler than in 2004 and probably similar to 2002. Flat areas were 50% snow covered about May 28, and snow free June 9. First flocks of Greater White Fronted Geese appeared 8 May, and first Brants (Branta bernicla) 24 May. Snow Geese (Chen caerulescens) started hatching about 24 June, Whitefronted 3 July, Semipalmated Sandpipers (Cal. pusilla) 4-8 July, swans 10 July.
|
|
|
|
|
|
| Date of 50%
snow-cover: |
28.05
|
|
| Date of ice-break on
rivers: |
|
|
| Date of final loss of
snow: |
9.06
|
|
BIOTIC
CONDITIONS
|
| Rodents abundance evaluation: |
low
|
|
|
Breeding conditions:
|
| Potential predators were the same as listed by J.R.Liebezeit for 2003 (pg. 23-24) plus a pair of local Rough-legged Hawks at Kuparuk and Red Foxes at both sites. Short-eared Owls were seen only during spring migration (quite commonly), Snowy Owls were uncommon during spring, common July 18-21, and not reported in meantime.
|
|
|
Rodent dynamics:
|
| I saw lemmings and voles in mouths and bills of predators (red and arctic foxes, ravens, gulls), throughout my stay.
|
|
Rodent species recorded:
|
|
|
|
|
Summary
of fauna studies: |
I wonder how much can we learn from monitoring the average size of geese broods seen throughout the season. For sure this approach has several limitations. First, it can work only in a place where observed broods are stationary and not transient, also a relatively large number of broods is needed. Even when these requirements are met this approach has weaknesses, as for one failed breeders would eventually leave the area and thus would not be counted, while later broods might tend to be larger and this might level out the effect of predator pressure on the earlier broods, especially during the first days of hatching. Despite all above, I think this method can give some idea about nesting success, especially when values from various years from the same location are compared. I tried this approach this year for Greater White-fronted Goose (A. albifrons) and some of my results are as follows:
Jul 9 m=4.1, n=18
Jul 11 m=3.7, n=46
Jul 22 m=3.7, n=53
Jul 26 m=3.0, n=36
Jul 27 m=2.8, n=23
As I mentioned I have no experience either with the species or with the method, but to me this looks like a relatively good success. Would appreciate your comments regarding this approach, especially critical ones.
|
|