Decking, patios and gravel gardens may be contributing to a decline in song thrushes, house sparrows and starlings, the RSPB has warned.
Leaving scraps out on a bird table could help save house sparrows
Conservationists said their numbers have plummeted over the last 30 years as a trend to replace lawns with a low maintenance alternative has taken off.
Without a habitat for insects, there is less for nestlings to feed on.
The RSPB said studies suggested this was threatening some species' survival rate and urged people to leave lawns.
It said that gardening makeover shows and a lack of time to spend tending a garden had led people to pave over their gardens or lay decking.
Front gardens covering an area roughly 22 times the size of Hyde Park have been paved over in London, while in the North East, nearly half of front gardens are covered, the RSPB said.
Plant a native shrub or climber
Leave patches of long grass
Do not cut back old stems of herbaceous plants and annuals until Spring
Fill a shallow dish with fresh water every day
Put nuts, seeds and household scraps in feeders or on bird tables
Richard Bashford, of the RSPB, said: "We are losing more and more of the natural environment around our homes, particularly our front gardens."
He said research had shown that even tiny front gardens or green verges are vital for urban wildlife and can house more than 700 different species of insect.
"The RSPB is still investigating the causes of declines and why bird populations aren't recovering. Currently there is no one factor this can be attributed to.
"However supplementing natural food with seeds and nuts and planting natural food sources for next spring can only help."
The RSPB is also urging gardeners to plant native shrubs, leave patches of long grass and introduce bird feeders and tables.