Tree Care and Maintenance
Seasonal Tree Care Tips: Winter 2022
Birds nest in a wide variety of places including tree branches, cavities, logs and stumps, on the ground, under shrubs, in open gravel, along stream banks, in chimneys, on bridges, ledges and light poles, and under the eaves of your house. Activities that threaten nesting birds are not limited to tree removal and pruning; mowing your lawn, clearing invasive or native vegetation from the ground, grading and building, or applying herbicides are all potentially disruptive.
The Migratory Bird Treaty Act (MBTA) of 1918 provides protection to all native bird species, even native species that are non-migratory. There are over 200 native bird species in the Portland area, including common species like robins and song sparrows, and less common species like flycatchers and bushtits. This Federal law, administered by the United States Fish and Wildlife Service (USFWS), makes it illegal to hunt, pursue, wound, kill, possess, or transport any native bird, their eggs, feathers, or nests, either intentionally or accidentally, without a permit from USFWS.
Nests are only protected when they are active, meaning when they contain eggs or young. Once fledglings have left the nest, the nest is no longer protected by law. In general, nesting season in our region is divided into three timeframes:
- August 1 – January 31 is the non-breeding season and the best time for site disturbing activities.
- February 1 – April 14 is early nesting season, a time to be aware of potential impacts and survey areas for active nests before conducting potentially disruptive activities.
- April 15 – July 31 is primary nesting season, a time to avoid disturbance if at all possible and survey sites for active nests when potentially disrupting activities are unavoidable.
The City of Lake Oswego does not have authority to administer or enforce the Federal MBTA, but we all have a responsibility to avoid active nests and delay potentially disturbing activities until birds have fledged. Most birds will leave the nest within about two weeks.
Visit these resources to learn more about the MBTA, what to do if you find a baby bird out of its nest, landscaping for native bird habitat, and more:
- Bird Conservation History, A Timeline of Important Dates in the Conservation of Migratory Birds, United States Fish and Wildlife Service
- Current list of MBTA protected species
- Living with Wildlife, information on how to live with wildlife provided by the Oregon Department of Fish and Wildlife, Wildlife Division
- Be on the Lookout for Nesting Birds: Springtime is Hatching Time, an April 2020 news release from the Oregon Department of Fish and Wildlife
- Protecting Nesting Birds, Best Management Practices for Vegetation and Construction Projects, Version 3.0, May 2017, City of Portland, Bureau of Environmental Services
Please check back for more seasonal tree care and maintenance advice!
Fall 2021: Healthy Trees are Defended Trees
Special Edition: After the Storm
Winter 2021: What is an Arborist?
Fall 2020: Soil Management
Summer 2020: Retaining and Creating Snags for Wildlife
Spring 2020: Mulch: Numerous Benefits and Easy Application
Winter 2020: Tree Planting: To Stake or Not to Stake?
Fall 2019: Insects and Diseases
Summer 2019: Drought Stress Revisited
Spring 2019: Trees and Construction
Winter 2019: Topped Tree
Fall 2018: Autumn Leaves
Summer 2018: Emerald Ash Borer
Spring 2018: Pruning Young Trees
Winter 2017: Tree Related Storm Damage
Fall 2017: New Tree Selection and Planting
Summer 2017: Trees and Turfgrasses
Spring 2017: English Ivy Removal
Winter 2017: Recognizing Tree Risk
Summer 2016: Drought Stress
Fall 2016: Preparing Trees for Winter
Additional Tree Care Resources:
|National Arbor Day Foundation||The Morton Arboretum|
|Oregon Department of Forestry||Tree Care Info|
|ISA Find an Arborist||Alliance for Community Trees|
|Oregon Department of Forestry|
Right Tree in the Right Place
Use this handy guide for assistance in choosing the right species of tree based on the constraints of a site, such as overhead wires, narrow plant strips, and proximity to structures.
"Right Tree Right Place" - helpful information such as "Use this guide for assistance in choosing the right species of tree based on the constraints of a site, such as overhead wires, narrow plant strips, and proximity to structures."
"Master Plant List" - a guide to the plants that are acceptable for mitigation requirements in Lake Oswego.