Need for more research on white-fronted terns

There is strong evidence that our white-fronted terns populations are in decline. Certainly in Canterbury I looked through some very large white-fronted terns flocks in January at the base of Kaitorete Spit. In one flock out of 750 birds I noted only two juveniles. Certainly overall the percentage of juveniles sighted was less than 5% out of over 3000 birds observed at various roosting locations in Canterbury in January. I think that recording the % of juvenile birds in white-fronted tern flocks in January, before juveniles disperse, (and possibly segregate from adults) would be an important tool to monitor nationally white fronted tern breeding success. Banding data to date suggests that White-fronted terns are long lived birds and this may be the factor keeping our white fronted terns population going. But is there sufficient recruitment for population viability ? I think we need to have more terns marked nationally to gain more in sight, especially regarding the bird's population age structure.