"It's not about building something new. It's about taking something that exists and altering it. It is more complex, more time-consuming, with more people to consult, more stakeholders, more complex problems, particularly with local governments," he said.
He cited the example of their office building, which used to be warehouses. The surroundings were all warehouses a decade ago but then gradually developed into part of the CBD.
The firm has many regeneration projects in Beijing including the Tanzhe Temple that is a heritage and tourism site, as well as industrial zones in the Yizhuang district.
Both examples involve designing solutions calling on many different views from land developers, local governments and consultants such as Atkins, which claims its strength from its global experience and local know-how in the field.
The firm regenerated east London for the Olympics. Birdsong said it was not just the games. As a sustainable development, it was actually the largest and newest park built in London in 200 years, which has an economic base to it and has transport links, with different levels of living conditions depending on income.
"We bring those skills not only from London, but from European cities, US cities, Middle East cities," he said.
"We bring this international know-how but couple it with local know-how."
About 90 percent of Atkins' staff are local.
"To work effectively in urban regeneration and build future-proofed cities, you have to understand the local conditions, how they function, how you relate to the local authorities and how you develop your personnel," he said.
Knowing how to work locally and within the local processes to actually get the best idea involves getting the best position, the best ideas with the best long-term economic forms to be successful, he added.
"When we talk about tourism, we hired a local university professor for that. We have to have local people in addition to ourselves. When they have a heritage issue, for example, we have a very capable lady in the UK who understands heritage very well. She actually came here to China to work with the Chinese government on the heritage of Chinese pottery because she also has expertise in pottery. That is the beauty of being local but international," he said.
The challenge is making a development fit into the culture. It is to fit those ideas together and come up with the best solution, both from an economic standpoint and from a positioning standpoint, he added.
Over the past three decades, China has grown quickly but the speed has been slowing down.