Bras d’Or res­i­dents make them­selves com­fort­able for win­ter

Cape Breton Post - - CAPE BRETON - An­na­marie Hatcher

Three types of mer­gansers call the Bras d’Or es­tu­ary their home.

It is Novem­ber in the Bras d’Or Lake Bio­sphere and in the Mi’kmaw cal­en­dar that is ‘Rivers start­ing to freeze time’ (Kepteki­wiku’s).

Al­though we at­tempt to track Mi’kmaw months as our com­mon months based on the Ju­lian cal­en­dar, they are not re­ally equiv­a­lent. There are ac­tu­ally thir­teen moon cy­cles in the tra­di­tional Mi’kmaw cal­en­dar ev­ery year.

Each cy­cle starts with the new moon and is named af­ter a sig­nif­i­cant en­vi­ron­men­tal oc­cur­rence at that time. So, Keptekewiku’s ac­tu­ally starts with the new moon around Oc­to­ber 22 this year in the Bras d’Or Lake Bio­sphere.

‘Rivers start­ing to freeze time’ is the time that thin ‘shell ice’ of­ten starts to form overnight in quiet fresh­wa­ter bod­ies, dis­ap­pear­ing when the sun’s rays warm it later in the af­ter­noon. This is a sig­nal to some of the bio­sphere res­i­dents that it is time to find a spot to hi­ber­nate, al­though the more or­ga­nized have al­ready picked their spots and made them­selves com­fort­able.

There are some brave Bras d’Or res­i­dents who stay and tough out the win­ter con­di­tions. Mak­ing them­selves quite vis­i­ble around the es­tu­ary shores in Novem­ber are gath­er­ings of mer­ganser div­ing ducks. They choose more se­cluded spots dur­ing the breed­ing sea­son.

How­ever, at this time of year, they gather in multi-species groups with other div­ing ducks, united by the com­mon drive to fill up with a meal of fresh fish. Their noisy less-than-grace­ful hunt­ing an­tics draw at­ten­tion to the gath­er­ings. Later in the win­ter these large ag­gre­ga­tions make it easy for young birds to meet mates. Their fran­tic dances take on a more ro­man­tic flavour, in­cor­po­rat­ing court­ing dis­plays with the fish­ing and feast­ing an­tics.

There are three types of mer­gansers ob­served around the Bras d’Or es­tu­ary. All three species are sex­u­ally di­mor­phic, mean­ing that the males and fe­males look quite dif­fer­ent. This makes field iden­ti­fi­ca­tion quite dif­fi­cult.

The most com­mon Bras d’Or mer­ganser is the red-breasted va­ri­ety, a skinny-beaked beauty with a crest on the back of the head rem­i­nis­cent of a ‘punk-style’ hairdo. This species loves the con­di­tions in the Bras d’Or es­tu­ary.

Much of the es­tu­ary of­fers safe, shal­low, salty wa­ter which is their pre­ferred habi­tat ac­cord­ing to the bird ‘bi­ble’ (Si­b­ley’s Guide to Birds, Na­tional Audubon So­ci­ety). The Mar­itimes are near the south­east­ern limit of the species’ North Amer­i­can breed­ing range,

ex­tend­ing through­out the bo­real for­est. This div­ing duck may look like our com­mon cor­morant or shag from a dis­tance. How­ever, it is smaller, with an adult length of about 58 cm com­pared to our com­mon cor­morant at about 84 cm.

At this time of year the adult male red-breasted mer­gansers have a rusty brown head with a long and ragged dou­ble crest, a pale chin, grey back, wings and tail and a white belly. Their bills are a beau­ti­ful scar­let-or­ange. The white patch in their wing is vis­i­ble in flight. The name ‘red­breasted’ refers to the colour sported by the adult males when in their breed­ing plumage, not nec­es­sar­ily at this time of year.

The com­mon mer­ganser is not ac­tu­ally as com­mon as the red breasted va­ri­ety in the Bras d’Or es­tu­ary. It is slightly larger than its red-breasted cousin (64 cm long) with a shorter, red­dish bill and a white chin. It may be dif­fi­cult to ob­tain a pos­i­tive ID un­less you see the two species to­gether.

Their bills are no­tice­able shorter and fat­ter than those of their red-breasted cousins. In other ar­eas of their range, the com­mon mer­gansers live mainly on fresh­wa­ter rivers and lakes. How­ever, the salty Bras d’Or es­tu­ary is a pro­tected win­ter habi­tat so many do over­win­ter here in open wa­ter ar­eas.

The third mer­ganser that may oc­ca­sion­ally be seen in the Bras d’Or Lake Bio­sphere is the hooded mer­ganser. It is a smaller duck, with an adult length of about 46 cm and is quite rare in the Bras d’Or es­tu­ary. It does have a crest but it looks more like a lump at the back of its’ head rather than a ‘punk’ crest. In the breed­ing male this lump forms an at­trac­tive fan.

The au­tumn ag­gre­ga­tions of mer­gansers around the Bras d’Or es­tu­ary fol­low schools of fish. They also eat other an­i­mals such as crabs, as well as some plant ma­te­rial. They are very co­op­er­a­tive and will some­times work to­gether to trap fish.

The mer­gansers’ eyes are adapted for un­der­wa­ter view­ing and they typ­i­cally swim along the wa­ter’s sur­face, re­peat­edly sub­merg­ing their heads to scan for food. The flocks of hunt­ing birds of­ten look quite fran­tic, div­ing to depths of up to five me­tres and catch­ing prey af­ter an un­der­wa­ter pur­suit. The long, slen­der bill can come in handy as a probe to ex­tract din­ner from un­der­wa­ter crevices.

Their co-op­er­a­tive na­ture is the rea­son that early spring ‘fam­i­lies’ of mer­gansers may fea­ture one or two adults and an un­be­liev­able pa­rade of duck­lings. Mer­gansers of­fer babysit­ting ser­vices to other fam­i­lies while the par­ents leave for fish­ing trips. I once counted an adult red-breasted mer­ganser with a tem­po­rary brood of 19 young­sters.

En­joy your walks along the shore at this time of year and keep your eyes open for the per­form­ing mer­gansers as they pre­pare for their com­mu­nal win­ter on the Bras d’Or es­tu­ary.


Red-breasted mer­gansers are shown in North­side East Bay, Bras d’Or.

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