Shettleworth and Krebs (1982)

Shettleworth, S.J. and Krebs, J.R. (1982). How marsh tits find their hoards: the roles of site preference and spatial memory. Journal of Experimental Psychology: Animal Behaviour Processes, 8, 354-75.

Expt 1 





 Expt 1
Each Marsh tit given bowl full of seed and allowed to store 12 seeds in 97 possible sites (in about 8 minutes) 2 to 3 hour interval Bird allowed 12 minutes to retrieve stored seeds. On average 4 birds got 8/12 by inspecting 30 sites.










Expt 2
Bird hides 8 seeds in 10 minutes 2 hour interval Bird hides 8 more seeds. 2 hour interval Bird allowed back to retrieve seeds









Conclusions Evidence
Birds do not use random search Few errors in recovery
They probably use memory Errors increase with seeds found
Probably working memory Birds avoid revisits and use no fixed path
Not just site preferences Not much visiting if no seeds present
Not dependent on cues from seeds Birds don't find them if E moves the seeds
Not fixed daily route They avoid already used sites when storing more
There is memory decay or interference There's a slight recency effect