SPRING SINGERS

Peep­ers her­ald the be­gin­ning of a new sea­son

Cape Breton Post - - Cape Breton - An­na­marie Hatcher Bio­sphere Dr. An­na­marie Hatcher is an ad­junct pro­fes­sor at Unama’ki Col­lege, Cape Bre­ton Univer­sity and a board mem­ber of the Bras d’Or Lake Bio­sphere Re­serve As­so­ci­a­tion. For more in­for­ma­tion

Colum­nist An­na­marie Hatcher tells us about the spring peep­ers.

The Mi’kmaw word for May is Squoljuiku’s which trans­lates to ‘frog croak­ing time.’

The sci­en­tific name for the Ji­jawej (north­ern spring peeper) re­flects its dis­tin­guish­ing fea­ture. The species name ‘cru­cifer’ means cross­bearer, be­cause of the ob­vi­ous X on their lit­tle backs. They are tiny frogs, weigh­ing in at about 4 grams with a body length of about 30 mm, which is slightly larger than a twoonie. Although the spring peeper is of­ten called a tree frog be­cause of its toe pads for climb­ing, it is usu­ally hid­den in the dense veg­e­ta­tion and leaf lit­ter around ponds and swamps at ground level.

In the Bras d’Or Lake Bio­sphere, the first calls of the north­ern spring peeper are anx­iously awaited as they her­ald a much-an­tic­i­pated change in the weather. North­ern spring peep­ers can be found from south­east­ern Canada through­out the east­ern United States as far south as north­ern Ge­or­gia. That all­male, love-sick cho­rus starts in March in the south­ern end of Nova Sco­tia but not un­til April and May in the Bras d’Or Lake Bio­sphere.

The Ji­jawej sym­phony that you hear near swamps and bogs is a cho­rus of the des­per­ate cries of male peep­ers long­ing to at­tract a mate. Af­ter they awake from their win­ter’s sleep, males will call fairly con­sis­tently at tem­per­a­tures rang­ing from 4 to 21o C. The fe­males lis­ten in­tently but do not call back. The louder cries come from the older, larger males who are anx­ious to pass their genes to the next gen­er­a­tion be­fore the end of their short life. North­ern spring peep­ers be­gin breed­ing in the first year af­ter they have hatched and can live an es­ti­mated three years in the wild.

That loud har­mony near the pond rep­re­sents a bal­ance be­tween singing a love song for a fe­male and de­fend­ing a singing spot from a male neigh­bour. The singing Romeo changes from a gen­tle chirp­ing sound to a more threat­en­ing, ris­ing trill when a male neigh­bour starts to in­vade its space. The sounds are made by in­flat­ing a vo­cal sac un­der the chin which ex­pands and de­flates like a bal­loon. Although it can be heard through­out the day in some places, the peeper cho­rus rises in in­ten­sity at dusk and dawn when amorous ac­tiv­i­ties are most vig­or­ous.

Why do the peep­ers raise their voices now and how can they muster up so much en­thu­si­asm so early in the spring? Two of our frogs, (wood frogs (Mi’kmaw: Samqwani’j)) and spring peep­ers, are anx­ious and ready to go as soon as the weather warms. They over­win­ter in the Bio­sphere, sur­viv­ing freez­ing tem­per­a­tures (down to -8 C) that are fa­tal to most other frog species. Spring peep­ers hi­ber­nate dur­ing the win­ter in soft mud near ponds, un­der logs and in holes or loose bark. In the late fall, when tem­per­a­tures near the freez­ing mark, they make their own

anti-freeze. They mo­bi­lize glu­cose from their liv­ers which causes blood glu­cose lev­els to in­crease dra­mat­i­cally. The glu­cose acts as a nat­u­ral anti-freeze for flu­ids around vi­tal or­gans. Frozen flu­ids are con­fined to outer parts of the body. Fi­nal ice con­tents as high as 70 per cent of the to­tal body wa­ter con­tent can be tol­er­ated by these freeze-tol­er­ant frogs. Unique cell mem­branes al­low ef­fi­cient move­ment and com­part­men­tal­iza­tion of the glu­cose-rich flu­ids. Frogs that are not freeze-tol­er­ant lack these adap­ta­tions. The heart of the frozen frog stops but is ca­pa­ble of start­ing up again with the gen­tle spring warm­ing. At that time, the in­ter­nal flu­ids re-dis­trib­ute around the body and the lit­tle heart starts beat­ing reg­u­larly af­ter the body thaws. All body sys­tems are then re-an­i­mated and the lit­tle male spring peep­ers start

their des­per­ate cries for love.

The faster and louder the male spring peep­ers sing, the greater the chances of at­tract­ing a mate. Fe­males lay any­where from 750-1,200 eggs which are at­tached to sub­merged plants. Males are happy to fer­til­ize the eggs as they are laid. De­pend­ing on the tem­per­a­ture, eggs can hatch within two days to two weeks. The tiny tad­poles have gills to breathe un­der­wa­ter and tails to help them swim. They will meta­mor­phose into young frogs and emerge in Au­gust and Septem­ber, join­ing their rel­a­tives hid­ing in the thick cover of plants cir­cling the wa­ter. Dur­ing the sum­mer and au­tumn the adult peep­ers live rel­a­tively soli­tary lives, be­ing mostly ac­tive at night and dur­ing moist, warm days. They don’t travel far, with home ranges that are from one to six me­tres in di­am­e­ter.

So, what de­ter­mines which ponds might make the best love-nests for these thawed peep­ers? In the Bras d’Or Lake Bio­sphere there are many suit­able spring peeper habi­tats. The best ponds are ones that are mainly open with en­cir­cling grass and small shrubs. Nearby sugar maples pro­duce a rich soup of wa­ter en­ter­ing the pond which will fuel the aquatic food webs. Other trees such as oaks pro­duce runoff that is not as at­trac­tive. A rich di­ver­sity of habi­tat pro­vides a va­ri­ety of perches for the male cho­rus and hid­ing places for the young tad­poles. In­ter­con­nect­ing ponds at the edge of a hard­wood for­est are ideal!

Am­phib­ians are in­di­ca­tors of en­vi­ron­men­tal change. Please help us keep an eye on the health of our Bio­sphere pop­u­la­tions. Be­come a Frog­watch vol­un­teer. Reg­is­ter at:

https://www.na­ture­watch. ca/frog­watch/

SUB­MIT­TED/AN­NA­MARIE HATCHER

This di­a­gram of the spring singers is by An­na­marie Hatcher.

This photo shows a north­ern spring peeper and can be seen at http:// no­vas­co­tia.ca/mu­seum/am­phib­ians/im­age.asp?id=75&spec=frogs.

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