Shortage of food or water? Why Okhla is seeing fewer winter birds this time

A bird watcher has said that the number of migratory birds at the Okhla Sanctuary this winter is lower than usual due to habitat disruptions. The bird watcher also said that there were fewer flocks of migratory birds this winter, including 1000 migratory birds of ten species - geese and duck species among them, but no waders. The bird watcher said that last year, in December, there were around 4000 birds of 20 to 25 migratory species at the Okhla Sanctuary. The bird watcher also said that we've seen barheaded geese and graylag geese, and smaller flocks of northern shoveler which used to be here in larger numbers. Apart from northern pintail, common teal, common pochard, tufted duck, and some great cormorants, the bird watcher said that we also recorded a flock of around 200odd blackheaded gulls which arrive in the daytime but do not stay longer. This may be due to a shortage of food and unfavourable habitat at the sanctuary. The bird watcher also said that migratory birds fly off due to disturbance from visitors and movement along the wetland. The bird watcher said that the main reason why migratory birds may not be resting