The efforts of the Wildlife Department to slow down the "aging process' of the shrinking Renuka Lake in Sirmaur district have started yielding results. The removal of weeds and measures taken over the past 10 years to check silting, which had reduced the effective area of the lake by over 25 per cent, has brought about a visible improvement in the national wetland. This became evident from the arrival of migratory birds in significant numbers this winter. Over 400 birds have descended on the lake for the winter sojourn.