Status and Occurrence of Manx Shearwater (Puffinus puffinus) in British Columbia
By Rick Toochin and Louis Haviland
Read the full article with photos here.
Introduction and Distribution
The Manx Shearwater (Puffinus puffinus) is a small species of shearwater found year round along both sides of the North Atlantic Ocean (Onley and Scofield 2007). This species has breeding colonies in Iceland, France, Faeroe Island, Ireland, Scotland, England, Channel Islands, Azores Islands, Madeira Island, and the Canary Islands (Onley and Scofield 2007). In eastern North America, the Manx Shearwater breeds in Newfoundland and is found in the Gulf of St. Lawrence to the Gulf of Maine (Lee and Haney 1996). Some of these birds winter in the North Atlantic Ocean off North America from the Carolinas to Florida, but most birds are trans-equatorial migrants from July to March wintering in the South Atlantic Ocean off Brazil to Argentina and spread across the South Atlantic to South Africa (Lee and Haney 1996, Onley and Scofield 2007). The Manx Shearwater has been undergoing a somewhat mysterious range expansion over the past few decades with more and more birds turning up in the North Pacific Ocean (Roberson 1996, Mlodinow 2004). Though breeding is suspected it has yet to be proven (Mlodinow 2004). One bird was tape recorded at night in a nesting burrow on Triangle Island by Dr. Ian Jones in the summer of 1994 (Mlodinow 2004). The bird was never actually seen and the bird’s identity was left unidentified for many years (P. Jones Pers. Comm.). Another possible breeding record comes from Alaska on Middleton Island on May 12, 2005, when 2 birds were seen together possibly prospecting for a nest site (Gibson et al. 2008). Records presumed to be this species have been slowly increasing since the late 1970’s and now the Manx Shearwater is an annually occurring species in small numbers along the West Coast of North America (Roberson 1980, Mlodinow 2004). One reason for the increasing detections is that Manx Shearwater frequents waters that are close to shore so it gets found quite often by observers (Lee and Haney 1996).
There are now over 79 accepted records of the Manx Shearwater in California by the California Bird Records Committee (Hamilton et al. 2007, Tietz and McCaskie 2014). In Oregon, there are 12 accepted records by the Oregon Bird Records Committee (OFO 2012). The Manx Shearwater is now so regular in Washington State, with over 37 records, that it was removed from the state review list in 2008 by the Washington Bird Records Committee (Wahl et al. 2005, WBRC 2012). In Alaska, the Manx Shearwater is currently listed in West (2008) as casual, but increasing in frequency in the waters off the state. In British Columbia, the Manx Shearwater has exploded in records since the mid 1990’s and now is classified as a rare to casually occurring species with over 50 records for the Province (Campbell et al. 2001, Toochin et al. 2014, see Table 1). Even though the Manx Shearwater is a truly pelagic species, it can be blown inland in eastern parts of North America after Hurricanes (Lee and Haney 1996). There is one incredible photographic record for Charlo, Montana found on May 30, 2004, at the Ninepipe National Wildlife Refuge (Holt et al. 2007).
Occurrence and Documentation
In British Columbia, there are 56 records from all along the coast of the province (Toochin et al. 2014, see Table 1). The sudden increase in British Columbia records of the Manx Shearwater since the 1990’s is a complex mystery. What makes deciphering older records difficult is that all were likely called Black-vented Shearwaters as the idea of a Manx Shearwater being seen in the Pacific Ocean was at one time unheard of (J. Fenneman pers. obs.). In our research of past accounts of Black-vented Shearwater, we found at least a few that had perfect descriptions for Manx Shearwater (Martin and Myres 1969). The Manx and Black-vented Shearwaters were split by the AOU in 1983 (AOU 1983). Since that time our identification and understanding of both species has drastically increased. It appears that Black-vented Shearwater is much rarer north of California and occurs in years of large water events such as El Nino (Small 2003). This is not to ever assume that all previously reported sightings of the Black-vented Shearwater are misidentified Manx Shearwaters. A reported Black-vented Shearwater seen by the author on a British Columbia Ferry on May 16, 1996, was seen by both observers at point blank range and Manx Shearwater was easily ruled out (Toochin 1998). Given the problematic nature of older Black-vented Shearwater records, it is probable that a few were in fact Manx Shearwaters (J. Fenneman pers. obs.).
The records for Manx Shearwater are from 3 main regions of the Province. There are 45 records for the waters near Vancouver Island, 11 records off the Queen Charlotte Islands, and 1 from deeper pelagic waters off Vancouver Island (Toochin et al. 2014, see Table 1). The number of records from the mouth of the Juan de Fuca Strait reflects years when extensive sea watches were conducted from 2006-2009 (Toochin et al. 2014, see Table 1). The Manx Shearwater was detected in May and June with the bulk of sightings coming from August to October (Toochin et al. 2014, see Table 1). It is possible that there are a few nesting pairs breeding on the Washington State side of the Juan de Fuca Strait (R. Merrill Pers. Comm.). This seems highly plausible given both the number of birds and frequency of sightings in the area.
The Manx Shearwater has also been found with more frequency on pelagic trips over the past 25 years from California to Washington State (Hamilton et al. 2007, OFO 2012, WBRC 2012). Given the explosion of occurrences in recent decades and the use of digital camera by observers, it is likely more Manx Shearwaters will be found in British Columbia as more observers look at seabirds. It is possible that this species will become common in future decades as the species continues to expand into the North Pacific. It should also be noted that records of Manx Shearwater are positively correlated with opportunities for pelagic boat trips off the coast.