- Pennie 1948
- Summer bird notes from Foula. Scott. Nat. 60: 157-163
- Peris 1995
- Shifts in the diet of grey heron (Ardea cinerea) in the Duereo Basin, central west Spain, following the introduction of exotic fish species. Folia Zoologica 44: 97-102
- , 1996
- Trophic interactions of squid Loligo forbesi in Scottish waters. In: Greenstreet S.P.R. and Tasker M.L. (Eds.) Aquatic Predators and Their Prey. Blackwell Scientific Publications, Oxford. 58-64
- Piersma 1988
- Body size, nutrient reserves and diet of Red-necked and Slavonian Grebes Podiceps griseigena and P. auritus on Lake IJsselmeer, The Netherlands. Bird Study 35(1): 13-24
- Piersma, Van Eerden 1989
- Feather-eating in Great Crested Grebes Podiceps cristatus: a unique solution to the problem of debris and gastric parasites in fish-eating birds. Ibis 131: 477-486
- Piersma 1988
- Foraging rhythm of great crested grebes Podiceps cristatus adjusted to diel variations in the vertical distribution of their prey Osmerus eperlanus in a shallow eutrophic lake in The Netherlands. Oecologia 76: 481-486
- Pilon 1983
- Summer food of the Great and Double-crested Cormorants on the Magdalen Islands, Quebec. Can. J. Zool. 61: 2733-2739
- Pitt 1922
- The Great and Arctic Skuas in the Shetlands. Br. Birds 16: 174-181, 198-202
- Platteeuw 1985
- Voedselecologie van de Grote (Mergus merganser) en de Middelste Zaagbek (M. serrator) in het IJsselmeergebied, 1979/80 en 1980/81. Rijp-rapport 48, Rijksdienst IJsselmeerpolders, Lelystad
- Platteeuw 1992
- Aalscholvers Phalacrocorax carbo in het Ketelmeer buiten de broedtijd: aantallen, prooikeuze en voedselaanbod. Limosa 65: 93-102
- Prime, 1987
- Quantitative assessment of gray seal diet from fecal analysis. A.C. Huntley, D.P. Costa, G.A.J. Worthy and M.A. Castellini (Eds): Approaches to Marine Mammal Energetics. Soc. for Marine Mammalogy Special Publ. No. 1: 165-181
- Prime, 1990
- The diet of grey seals from the south-western North Sea assessed from analyses of hard parts found in faeces. J. Appl. Ecol. 27: 435-447
- Prüter 1989
- Phänologie und Ernährungsökologie der Dreizehnmöwen (Rissa tridactyla) - Brutpopulation auf Helgoland. Ökol. Vögel 11: 189-200