To determine whether Hudson Bay‐Foxe Basin bowhead whales segregate on the basis of age, whales summering in northern Foxe Basin, were aerially photographed in August of 1996, 1997, and 1998. Image lengths on either the negatives or contact prints were measured and total body lengths were estimated. In all three years the majority of whales photographed were ≤13.5 m long. Calves and juveniles made up 89.3%, 96.6%, and 79.3% of the total number of measured whales in 1996 (n = 28), 1997 (n = 30) and 1998 (n = 29) respectively. The number of bowheads >13.5 m, the approximate size at which females reach sexual maturity, that were photographed was directly proportional to the number of calves photographed. Our results indicate that northern Foxe Basin bowheads are part of a more widely distributed stock. Adult males and resting adult females apparently summer in another part of the range, probably northwestern Hudson Bay. Northern Foxe Basin appears to be used as a summer feeding area by cows with young‐of‐the‐year calves and by juveniles.

ABSTRACT. There is interest among the Inuit of Nunavut in renewing subsistence hunting of bowhead whales. Managing a limited harvest while allowing for stock recovery from commercial whaling requires some estimate of stock numbers. The large geographic range of bowhead whales in the eastern Canadian Arctic precludes cost-effective estimation of total stock size; however, estimates of summer aggregation sizes can be derived from sampling of summering areas. Although these numbers do not represent total stock size, they do provide indicators of the minimum number of bowheads known to be present and may be useful as indices for monitoring stock recovery. A visual aerial survey conducted in northwestern Hudson Bay resulted in an estimate of 75 ± 27.5 (95% Confidence Interval = 17-133) bowhead whales. This estimate is conservative because it was not corrected for submerged whales or for whales that were at the surface but not seen by observers. Most sightings of whales were made in Repulse Bay and Frozen Strait.Key words: aerial survey, bowhead whale, distribution, northwestern Hudson Bay, stock size RÉSUMÉ. Parmi les Inuit du Nunavut, on s'intéresse à reprendre la chasse de subsistance à la baleine boréale. La gestion d'une récolte limitée, qui permettrait au stock de baleine boréale de se rétablir des effets de la pêche commerciale, demande qu'on ait une idée du nombre d'individus qui composent cette population. L'ampleur du territoire géographique de la baleine boréale dans l'Arctique canadien oriental écarte la possibilité de réaliser une estimation du nombre total d'individus, qui soit efficace en terme de coûts; il est cependant possible de dériver des estimations de la taille des concentrations estivales à partir d'échantillonnages de zones d'estivage. Bien que ces nombres ne représentent pas la taille totale du stock, ils fournissent des indications sur le nombre minimum de baleines boréales dont on a attesté la présence et ils peuvent servir d'indicateurs pour la gestion du rétablissement du stock. Un relevé visuel aérien mené dans le nord-ouest de la baie d'Hudson a donné une estimation de 75 ± 27,5 (intervalle de confiance de 95 p. cent = 17-133) baleines boréales. Cette estimation est prudente car elle n'a pas été corrigée pour tenir compte des baleines submergées ou de celles qui étaient en surface mais qui n'auraient pas été aperçues par les observateurs. La plupart des observations de baleines ont été faites à Repulse Bay et Frozen Strait.Mots clés: relevé aérien, baleine boréale, distribution, nord-ouest de la baie d'Hudson, taille du stock Traduit pour la revue Arctic par Nésida Loyer.

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Vocal development was followed in laboratory-reared American Coots (Fulica americana). Four call types were observed in young chicks: twitter, wit-ou, squawk, and yeow. During the first month all calls showed changes in pitch. Call duration showed no change in the twitter and yeow calls, but showed an increase in both the wit-ou and squawk calls. Twitters were dropped from the repertoire after 30 days of age, whereas yeow calls were dropped after about 2 months of age. When approximately 2 months old, juveniles used three calls, one derived from the squawk, and two derived from the wit-ou. Sexual dimorphism also developed when birds were about 2 months old. By 3 months of age, juvenile calls resembled those of adult coots.

In 1986, we recorded the MV Arctic, CCGS des Groseilliers and MV Lady Franklin during routine icebreaking operations and travel to and from the mine at Nanisivik, Baffin Island, Northwest Territories, Canada. We found that the Arctic generated more high frequency noise than did the other vessels we recorded. Monitoring of vessel noise levels indicated that belugas and, probably, narwhals should be able to detect the high frequency components of Arctic noise at least as far as 25 to 30 km from the source. The ability of whales to detect the MV Arctic at long distances may explain why belugas and narwhals in Lancaster Sound seem to react to ships at longer distances than do other stocks of arctic whales.