KWA NTHAWI yaitali anthu ambiri akhala akukhulupirira kuti mbalame zotchedwa Arctic Tern zimauluka pafupifupi mtunda wa makilomita 35,200 pa ulendo wawo wochokera kumpoto kwenikweni kwa dziko lapansi ku Arctic, kukafika kum’mwera kwenikweni ku Antarctica n’kubwereranso. Koma kafukufuku waposachedwapa, wasonyeza kuti mbalamezi zimauluka mtunda wautali kwambiri kuposa pamenepa.

Pofuna kudziwa mtunda umene mbalame za mtunduwu zimauluka, ofufuza anamangirira tizipangizo tating’ono kwambiri toyezera mtunda pa mbalame zina. Tizipangizoti tinasonyeza kuti mbalamezi zimauluka mtunda wa makilomita 90,000 paulendo wochoka ku Arctic komanso kubwerera. Palibe nyama iliyonse imene inayendapo mtunda ngati umenewu. Anapezanso kuti mbalame ina inauluka pafupifupi makilomita 96,000.

Mbalamezi zimauluka mokhotakhota paulendo wawowu. Moti njira imene zimatsatira zikamauluka podutsa panyanja ya Atlantic imaoneka ngati chilembo cha “S.” Zimauluka mokhotakhota potengera mmene mphepo ya panyanjayo imayendera.

Mbalamezi zimakhala ndi moyo pafupifupi zaka 30 ndipo pa nthawiyi zimakhala zitauluka mtunda oposa makilomita 2.4 miliyoni. Mtunda umenewu ndi wofanana ndi kupita ku mwezi n’kubwerako, maulendo atatu kapena 4. Wochita kafukufuku wina anati: “N’zochititsa chidwi kwambiri kuona kuti kambalame kolemera magalamu oposa 100 okha, kamauluka mtunda wautali chonchi.” Buku lina linati: “Chaka chilichonse mbalamezi zimakhala ndi nthawi ya masana yambiri kuposa cholengedwa chilichonse” chifukwa choti pa nyengo yotentha zimapezeka kumpoto kwenikweni kwa dziko lapansi ndipo zikapita kum’mwera zimakapezanso nyengo yomweyo.​—Life on Earth: A Natural History.