between mid-March and early-April. Knot numbers at Miranda gradually decline until only an over-wintering flock of about 500 birds remains. Wader censuses Since 1960 wader censuses at Miranda take place twice a year, in November and June. The breeding areas of the migratory birds often have a dispersed nature. The only opportunity for any form of population monitoring is during the non-breeding season when the birds congregate in places like the tidal regions of the Firth of Thames. Counting of the shorebirds at the high tide roosts over longer periods of time can give a good indication of the population trends. The figures can be used when discussing the conservation of wetlands along the migratory routes. The datasets collected at Miranda is one of the longest available. In 1983 the Ornithological Society of New Zealand (OSNZ) initiated a national wader count scheme. This scheme was continued until 1994 and then reinstated for the period from 2004 to 2009. Miranda Shorebird Centre The Miranda Shorebird Centre can be found on the west side of the road between Miranda and Kaiaua. It's open to visitors all year, and it has information displays on wader birds of the Firth of Thames. It also houses a shop, which offers a collection of books on birds and birding and bird related souvenirs. The centre has a library, that is open to use for research purposes. The centre offers low budget accommodation in the forms of bunkrooms and self-contained units for individuals and (small) groups. Keith Woodley is the centre manager since 1 May 1993. Visitor numbers have developed from 3,000 in 1993 to 16,000 in 2008. Bird hide A hide for observing the birds stands 2 km south of the centre. It overlooks the shellbanks where large numbers of godwits, knots and other shorebirds roost at high tide. During a large part of the season a guide of the Shorebird Centre is stationed at the hide around high tide. The guide assists visitors who want to learn to know the birds. Binoculars, and a telescope are available, so that visitors can have a close look at the birds. Volunteers had been guiding in the past, but since 2009 this is done by the Shorebird Centre assistant. Between October 2010 and April 2011 during 85 days the number of visitors during approximately 3 hours over the high tide were counted. These numbers counted up to 2150.