388 



Gh'lhil CUinute Chcinac — Our Living; Resources 



AS part of the joint United States-Canada 

 eft'oils to monitor populations of Arctic 

 geese and to provide data necessai7 to set 

 hunting regulations, scientists have recorded 

 not only goose population levels, but also 

 nesting behavior. Maclnnes et al. (1990) 

 analyzed data from four long-term studies of 

 five different Arctic goose populations. 

 These studies documented the date the eggs 

 hatched and the clutch size (number of eggs 

 per nest) over 35 years (Fig. I ). 



The dates of nest initiation and hatch are 

 clearly affected by climate and are delayed 

 by cold weather. The records not only show 

 wide fluctuations from year to year in 

 response to annual variations in climate, but 

 also demonstrate a consistent trend toward 



Fig. 1. Location of four monitoring sites. Sites 

 chosen represent localities with information for 5 

 or more years. Site 1-McConnell River 

 (60° 50'N. 94' 25"W; snow goose \Chen 

 caerulescens] and small Canada goose [Bninto 

 canadensis]): 2- La Perouse Bay (?S" 24" N. 94 

 24'W; snow goose); .^-Cape Churchill (58" 25'N. 

 93°W; medium Canada goose); and 4— South- 

 hampton Island (63° 60'N, 86°W; .snow goose). 



Changes in Nesting 

 Behavior of Arctic Geese 



by 



Edward T. LaRoe 



Donald H. Rusch 



National Biological Service 



earlier hatching over the period (Fig. 2). 

 Young Arctic geese today, on the average. 

 hatch about 30 days earlier than they did .35 

 years ago; during the same time, average 

 clutch size has shrunk (Fig. 3). Maclnnes et 

 al. ( 1990) suggest the change in nest date is 

 a result of climatic amelioration, that is. 



- Southhampton snow goose 

 ■ La Perouse Bay snow goose 



warming (although whether from a long- 

 term trend or short-term cycle is unclear), 

 and the change in clutch size is a result of 

 habitat deterioration. 



Reference 



Maclnnes. CD.. E.H. Dunn. D.H. Rusch. F. 

 Cooke, and F.G. Cooch. 1990. Advancement of 

 goose nesting dates in the Hudson Bay Region. 

 I9.SI-86. Canadian Field Naturalist 104:295- 

 297. 



For further information: 



Donald H. Rusch 



National Biological Service 



226 Russell Labs 



1630 Linden Drive 



Madison. WI 53706 



McConnell Riuer snow goose 

 McConnell River Canada goose 



05/06 



05/16 



05/26 



06/05 



06/15 



06/25 



1950 



I — I — r~ 

 60 



Year 



70 



80 



Fig. 2. Date of first egg. Although all sites displayed large fluctuations 



the mean (average) hatch date became significantly earlier during the period 1951-86. There were no 



significant differences in the slopes of trends among sites or species. 



— Southhampton snow goose 



— La Perouse Bay snow goose 



— Churchhill Canada goose 



McConnell River snow goose 

 • McConnell River Canada goose 



5.0 



3.0 ■ 



50 



55 



60 



-T — \ — I — rn — r 



65 70 



Year 



-n — I — I — nT— 1 — r- 



75 80 



"T — i — r- 



85 



Canada goose (Branta canadensis). 



Fig. 3. Clutch size of nests of snow and Canada geese at Hudson Bay. 



