Conservationists say worsening haze in Malaysia and elsewhere in Southeast Asia is causing problems for animals, especially migratory birds.

Now is the time when birds move from their breeding grounds to their wintering grounds. Their trips are made using a combination of navigational skills -- innate mental maps, as well as visual, electromagnetic and astronomical cues.

Heavy smog and haze created by poorly regulated industry and auto traffic in Southeast Asia are disrupting traveling birds' ability to see the visual and astronomical cues they rely on.

"People think the haze has caused them problems but animals, in particular migratory birds, have it much worse," Vincent Chow, Malaysian Nature Society Johor chairman, told reporters. "They need to see the stars to guide them from East Asia to South-east Asia, making their way to the coastline of Johor to find food such as small fish."

Chow says the smog can also prevent animals on the ground from successfully foraging for food.

While Chow doesn't cite new scientific evidence on the subject, previous studies have proven the potential problems man-made pollution can cause migrating birds.

Research has shown growing light pollution disrupts the biological clocks and behaviors of a range of birds and mammals, and a 2014 study in Denmark suggested AM radio waveband electromagnetic interference can drown out the magnetic compass of robins.

Malaysia is an important stopover point in the middle of the East Asia-Australasia Flyway, an expansive north-south migratory route -- from Australia up along East India and Southeast Asia, and north towards China and Mongolia -- used by some 50 million birds and nearly 500 species.