Canada Goose - 2019 WeBS

The peak of 1669 on the Cleddau occurred in June 2007.  The peak during the 'normal' count season of September to March was 651 in December that year.  During the 2010s, the peak count on the Cleddau has been in June or July.

Canada Geese did not appear regularly in WeBS counts on the Nevern Estuary until 2003-04.  Maximum counts of between 1250 and 1500 have occurred several times in September-October since 2013-14.  Counts are still low outside of this period, with none recorded in November-January, although there have been occasional counts of less than a dozen in mid-winter on non-count days. 

Counts on the Teifi Estuary have numbered in the 100s since 2000, steadily increasing to 1000 in September 2010-11.  Since then, there have been several counts of over 1000, all in the September-November period.  It is possible that these are birds that were at the Nevern earlier in the season.

Generally small numbers (less than 50) occur on fresh-water sites.  However they are more regular on LLys-y-Fran (up to 400) and on Marloes Mere (370 in 2010-11 but more usually less than 100).

Counts of Canada Geese can be surprisingly low at any site due to their habit of moving away to feed in fields, often some distance from the water, during the day.

National trend

The WeBS national trend for Canada Goose show a massive increase in the Welsh population in the late 1990s, however the overall British trend showed only a slow increase at that time.  The English popluation remained relatively stable, suggesting that a part of the increasing population has moved to Wales.

Canada geese across Britain have shown a typical population curve of a “new” species, whether introduced by man or by natural expansion.  Initially they remained at a relatively low level as the population established itself, followed by a rapid rise, and then (since around 2000) a levelling out as the population reaches the maximum carrying capacity of the habitat.

As the numbers of geese have increased, they have increasingly fed away from the estuary and are often missed during a count.  This may account for a low peak number in some years, and it is difficult to know if this is a true indication of the population change, or just half the birds being elsewhere. 

Are they causing a problem?

Some studies have been undertaken in other parts of the country regarding their effect on other wild birds using the same water bodies.  This research suggests that even large numbers of Canada geese have no effect on other species of wildfowl.  The increased population on the Cleddau does not, at present, appear to be having any effect on the overall numbers of wildfowl in the areas they occur.  However, there may be an effect on the vegetation from trampling and eutrophication.

Canada Goose 2003-07

Canada geese were introduced into Pembrokeshire in 1955, at Boulston, on the Western Cleddau and in 1957 at  Orielton, where they continued to breed until 1977. The Boulston group became well established, with 30 geese present in 1968, 78 in 1971 and 159 in 1986.  Pairs bred at Haroldston West and on Sheep Island in 1976, although at this time, the population was still generally confined to the upper Daugleddau Estuary, which they seldom left. Between the 1984-88 and 2003 - 07 tetrad surveys the Canada goose population underwent a significant expansion in range, as shown on the tetrad map.

The tetrad map for 2003-07 shows that as a breeding species, Canada geese are now widely spread across the county. They are opportunistic colonisers and breeding pairs have become established on farm irrigation reservoirs and large ponds with nesting islands and grazing close-by.  Breeding pairs have also taken up residence on some of the small rocky islets off the mainland coast of Pembrokeshire, as well as on the islands of Skokholm and Skomer.

In 2003-07, breeding was confirmed in 52 mainland tetrads. Assuming a nesting density of at least one pair per tetrad, and taking into account the 16 pairs on the two islands, the breeding population in 2007 was at least 68 pairs, and may have been closer to 100 pairs.

Jane Hodges

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 52

Orange = breeding probable = 18

Yellow = breeding possible = 24

Total tetrads in which registered = 94 (19.2%)

Canada Goose - 1994

 Breeding resident

The first record for this species was of four at Skokholm on 3 October 1952. Their origin is unclear, since Canada Geese were not introduced until 1955 at Boulston and 1957 at Orielton. They continued to breed at Orielton until 1977 but have apparently not done so since. The Boulston group has become well established and has built up from 30 in 1968 to 78 by 1971 and 159 by 1986. Although single pairs bred at Haroldston West and Sheep Island in 1976 . the population otherwise remained confined to the upper Cleddau Estuary. They began to spread in 1984 and by 1988 their breeding distribution was as shown on the map. Breeding productivity has been low with up to ten fledglings being recruited per year.

Canada Geese return to the upper Cleddau to moult and are seldom recorded away from that area in the winter. The occasional records from the Pentood area, the Gwaun, Llysyfran reservoir and Maenclochog are thought to be attributable to wanderers from the group that is resident at Newcastle Emlyn, Ceredigion, while a flock of about 70 seen at several localities between Dinas and Strumble Head in September 1989 occurred at a time when Canada Geese were absent from Newcastle Emlyn.

Fieldwork 1984-88 (based on 478 tetrads)

Red = breeding confirmed = 6

Orange = breeding probable = 5

Yellow = breeding possible = 5

Total tetrads in which registered = 16 (3.4%)

Donovan J.W. & Rees G.H (1994), Birds of Pembrokeshire

Canada Goose - 1970s breeding

Red = breeding confirmed

Orange = breeding probable

Yellow = breeding possible

Canada Goose - 1980s winter atlas

 

The BTO winter atlas showed that Canada Geese were present in only one 10km square during the winters of 1981-82, 1982-82 and 1983-84. 

The mid blue colour in the square represents over 27-121 birds recorded in a day. About 100 Canada Geese remained in the Boulston area of the Western Cleddau which is where they were introduced in 1955.

Graham Rees