Summary of Specifications:
The Migratory Bird Treaty Act of 1918 (MBTA) protects over 800 species of birds, including virtually all common songbirds, waterfowl, shorebirds, hawks, owls, eagles, ravens, crows, native doves, swifts, martins, swallows and others, including their body parts (feathers, plumes etc.), nests, and eggs. The only non-game birds likely to be encountered in Colorado that are not offered protection under the MBTA are introduced species: European Starlings (Sturnus vulgaris), House Sparrows (Passer domesticus), and the common pigeon (Columba livia), also known as Rock Dove. Game species receive protection, under state wildlife regulations.
The MBTA makes it unlawful "to hunt, take, capture, kill… [or] possess" any bird protected by the Act. The term take applies to both intentional and unintentional acts, and is defined as "to pursue, hunt, shoot, wound, kill, trap, capture, or collect, or attempt to pursue, hunt, shoot, wound, kill, trap, capture, or collect." CDOT’s interest in the MBTA stems largely from the fact that MBTA protection includes not just birds, but also "any part, nest, or egg of such bird, or any product, whether or not manufactured, which consists, or is composed in whole or any part of any such bird or any part, nest, or egg thereof." Many Colorado Department of Transportation (CDOT) bridges, culverts and other structures contain active nests, and those structures require maintenance, replacement or other construction efforts, often during the active nesting season. The US Fish & Wildlife Service (USFWS), responsible for administering the MBTA, does allow the removal of inactive nests for some species of birds without a depredation permit as per a 4/15/2003 memorandum submitted by the Director of the Department of the Interior. But any active nest (a nest containing an egg or young) cannot be removed or interfered with, if that interference results in take
Typically, CDOT construction and maintenance activities occur during warmer weather, which closely coincides with the nesting season for birds. This presents conflicts between the construction/maintenance work and CDOT’s efforts to comply with the MBTA. CDOT attempts to avoid, minimize and mitigate impacts to wildlife during design and through construction. During engineering design, CDOT environmental managers consider the presence of active and/or historic nests on structures such as culverts and bridges, as well as within vegetation to be cleared and/or grubbed. When warranted, CDOT’s Section 240 Project Special Provision for the Protection of Migratory Birds is included in advertised project specifications. The inclusion of the 240 Specification requires that wildlife biologists survey bridge structures prior to construction activities to be performed during the migratory bird breeding season, defined as April 1-August 31. Pre-construction nest surveys ensure that bridges are free of active nests and places the liability for the monitoring of and maintaining nest-free bridges on project contractors. Contractors are encouraged to (1) schedule activities outside of the breeding season, (2) begin work before the breeding season, and (3) attempt to prevent nests from becoming active prior to and during work. On many projects, monitoring and excluding birds is relatively simple. A variety of best management practices (CDOT Report 2010-7 Bird Nesting and Droppings Control on Highway Structures) have been used to exclude birds from concrete box culverts. However, on large bridge structures, given the difficult location (height, inaccessibility of nests, etc.) the third option, preventative measures to deter nesting, are not always viable and the first two options involving seasonal activity restrictions cannot be implemented on a consistent basis due to project schedules, weather constraints, budgetary concerns and equipment availability.
The penalties for causing a migratory bird take are criminal, and expensive, and the crime is a strict liability crime, which means that it can still be prosecuted even if there is no intent of take. CDOT engineers have difficulties trying to incorporate migratory bird nest removal activities into their projects from a budgeting and scheduling standpoint, and contractors have a difficult time keeping bridges "bird-free." Issues with complying with the MBTA can affect projects in other ways as well, including water quality, labor, and health and safety. In addition to the MBTA, other species such as raptors, are subject to Colorado Parks and Wildlife (CPW) guidance which further limits work within temporal or spatial buffers.
Because bridge projects such as reconstruction, deck rehabilitation, even asphalt overlay projects, have the potential to cause migratory bird takes, the presence of even one migratory bird nesting on a bridge can cause project delays and cost overruns due to monitoring and removal efforts. Preventing the establishment of nests on structures brings significant challenges as well, ranging from the types of birds (colonial or non-colonial nesters), the locations of nests (some bridges are high, others over water, etc.) the need to monitor regularly (at least twice a week) and difficult access to nests.
To address these issues CDOT would like to identify innovative methods to remove inactive migratory bird nests from large bridge structures prior to the migratory nesting season; and to monitor active nests during the migratory bird breeding season when necessary. CDOT would also like to better support its decisions regarding bridge activities that are not expected to effect nesting (such as bridge surface repairs).
CDOT Region 1 Planning and Environmental initiated a study in 2012 and 2013 to gather information about all bridges where construction was planned. A contractor was hired to monitor some of those bridges and remove nests when encountered. The monitoring data collected include information about the types and characteristics of structures supporting nesting birds, the approximate arrival times of different species, the length of gestation/fledging periods based on observation of nest activity, a variety of procedures used to monitor and remove nests from bridges and the approximate departure date for migratory species. In addition, data associated with the costs of monitoring will be provided to the Principle Investigator (PI) if needed.
These data can be incorporated into this study (if desired) to develop a toolbox of practical best management practices (BMPs) that CDOT can use to prevent nesting on accessible structures when repair or replacement is needed.
