Newly trained census workers and census-tardy residents alike appear to be working through some opening week jitters as the U.S. Census Bureau's massive door-to-door campaign picks up steam and heads into the summer.

The operation began Saturday and will continue through July as census enumerators try to reach every household that did not return a 2010 Census questionnaire through the mail.

Local census officials emphasize that getting a complete count of the local population is crucial not only for congressional apportionment, but also for the state to receive its fair share of federal funding for social services and other programs.

Census enumerators say their efforts are being hampered by residents who say they are too busy or who are wary of speaking to strangers.

Census workers have also said they've experienced difficulty gaining access to secured buildings.

"There are some first-day jitters, both for our enumerators as well as people who are seeing us at their doors," said Winnie Wilson, manager of the Honolulu Census Office. "But a lot of people have been very cooperative. There hasn't been any blatant screaming at us that I've heard of."

Wilson said the issues with secured buildings will be resolved as enumerators continue to work with building managers to schedule visits.

Census enumerators are leaving printed notices at residences if they are not able to make contact with people there. Wilson said her office has fielded several calls from residents seeking to confirm the authenticity of these notices.

Census enumerators carry an official census badge for identification . The badges do not have a photograph of the worker, but residents have the right to ask the worker to show a picture identification such as a driver's license.

"If there's a question, or if they want to confirm that the person at the door is really a census worker, they can always call us," Wilson said.

While previous census safety tips stated that workers will also come equipped with an official census bag and a handheld device, Wilson said census workers may not carry the bag to every visit and that the handheld devices (which have been reported to have caused data overloads and other problems in some states) are not being used in the current enumeration operation.

Enumerators will not ask to come inside the home (and are not allowed to enter even if asked) and will only collect information directly related to the 10 questions on the 2010 Census questionnaire. They will not ask for Social Security numbers, bank account information, immigration status or any other personal information.

Wilson noted that there are other survey efforts under way that are not related to the 2010 Census.

"Our main concern is to count," Wilson said. "That's all we're interested in."