Sikes Act Reauthorization Act of 2003

Sikes Act Reauthorization Act of 2003 - Amends the Sikes Act (which requires the Department of Defense and the U.S. Fish and Wildlife Service to develop and implement plans to manage natural resources on certain military lands) to reauthorize appropriations and expenditures for FY 2004 through 2008 for conservation programs on military installations.

Declares the sense of Congress that the Secretary of Defense should take whatever steps are necessary to ensure full implementation (consistent with the findings of this Act) of the Sikes Act requirement that sufficient numbers of professionally trained natural resources management and law enforcement personnel be available and assigned responsibility to perform tasks necessary to carry out conservation programs on military installations, including preparation and implementation of integrated natural resource management plans.

Requires the Secretary of a military department to advise the Secretary of the Interior and the head of the appropriate State fish and wildlife agency of intent to prepare or revise an integrated natural resources management plan.

Requires the Secretary of the Interior, the head of the appropriate State fish and wildlife agency, and the Secretary of the military department that prepares or revises the plan each to certify that the plan they agree upon adequately addresses conservation, protection, and management of the fish and wildlife resources.

Requires the Secretary of a military department to publish notice and provide an opportunity for public comments of the intent to prepare or revise an integrated natural resource management plan.

Requires that an integrated natural resource management plan in Guam provide for management, control, and eradication of invasive species that are not native to the ecosystem of the military installation, and the introduction of which cause or may cause harm to military readiness, the environment, the economy, or human health and safety.