Golden-crowned sparrows are a medium-sized sparrow found along the Pacific coast of North America. They breed in Alaska and northwest Canada and migrate south to winter along the coast from southern British Columbia to Baja California. Their preferred nesting habitat consists of brushy thickets and forest edges near water. Let’s take a closer look at where exactly golden-crowned sparrows build their nests.
Nesting Range
The breeding range of the golden-crowned sparrow extends across Alaska and northwestern Canada. Their nesting grounds center around the following regions:
- Southeastern Alaska
- Southwestern Yukon Territory
- Northwestern British Columbia
- Western Northwest Territories
Within these broad regions, golden-crowned sparrows seek out appropriate nesting habitat, which is typically found near water sources. They are most abundant in areas with extensive thickets and shrubbery interspersed with open meadows and wetlands.
Coastal Habitats
Throughout their Alaskan and Canadian breeding range, golden-crowned sparrows show a strong preference for nesting in coastal areas. Coastal tidal marshes, estuine shrublands, and wetlands along the seashore provide ideal nesting conditions. These habitats supply the dense vegetation and proximity to water that golden-crowned sparrows rely on when breeding.
Some specific coastal nesting areas used by golden-crowned sparrows include:
- The Cook Inlet region of Alaska
- Prince William Sound and the Copper River Delta in southern Alaska
- The wetlands of the Yukon-Kuskokwim Delta in western Alaska
- The outer Aleutian Islands
- Coastal inlets and bays along the British Columbia coast
Nesting golden-crowned sparrows flourish in these coastal wetland ecosystems. The brushy, marshy environment supplies everything they need to successfully build nests and raise young.
Inland Habitats
While coastal regions comprise the main nesting grounds of golden-crowned sparrows, they will also inhabit and breed in certain inland habitats. These include:
- River valleys and lake shores of southwestern Yukon
- Subalpine scrublands and meadows of northwestern British Columbia and Alaska
- Early successional forests and forest clearings
- Regenerating areas recently burned by fire
Although inland sites are secondary to coastal areas, golden-crowned sparrows readily adapt to these varied environments when suitable vegetation exists. The presence of low, dense shrubbery amid wetter zones allows them to nest successfully far from the ocean as well.
Specific Nest Sites
Once they arrive at their general nesting territory, golden-crowned sparrows search for specific sites to build their nests. Preferred locations include:
- At the base of stumps or small trees
- In low, thick shrubs like alder or willow
- Supported by multiple upright branches
- Concealed by overhanging vegetation
- Close to openings and edges
- Near water sources like streams, ponds, or wetlands
Choosing a well-hidden site with a sturdy, elevated foundation allows golden-crowned sparrows to construct secure nests safe from predators and flooding. Ideal sites provide cover while also allowing easy access for the parents to come and go when feeding nestlings.
Nest Description
The nests built by golden-crowned sparrows are compact, cup-shaped structures about 4-6 inches across. They are constructed from grasses, mosses, lichens, and twigs, then lined with finer materials like sedges and animal hair. Both the male and female participate in nest building, which takes 4 to 9 days to complete.
Here are some key facts about golden-crowned sparrow nests:
- Outer layer made of coarse grasses and twigs
- Lined with fine sedge, moss, and animal hair
- Typically 4-6 inches in diameter
- Built 4 to 9 feet above ground
- Well-concealed in thick vegetation
- Used for one brood per season
This careful construction results in durable, long-lasting nests that successfully house golden-crowned sparrow clutches and protect the hatchlings as they develop.
Clutch Size and Incubation
Once their nest is completed, the female golden-crowned sparrow lays a clutch of 3-5 eggs. She will incubate them for 11-13 days while the male helps feed her. Some key facts about their clutch size and incubation:
- Clutch size ranges from 3-5 eggs
- Eggs are pale blue-green with brown speckles
- Only the female incubates the eggs
- Incubation lasts 11-13 days
- Hatchlings are altricial at birth
This moderate clutch size allows the parents to adequately care for and feed the nestlings. The female’s dedicated incubation ensures development and hatching success for each breeding cycle.
Nesting Timeline
Golden-crowned sparrows follow a regular nesting and breeding seasonal timeline throughout their range. A typical schedule is:
- Early May: Arrival at northern nesting grounds
- Mid-May: Males establish territories, females build nests
- Late May: Egg laying and incubation begins
- Early June: Hatching of young
- Mid-June: Nestlings fledge and leave nest
- July: Finish raising first brood, may build second nest
- August: Departure for wintering grounds
Nesting is timed to match the short boreal summer and maximize food availability. Two broods may be raised in a season if conditions allow.
Adaptability
One key trait that enables golden-crowned sparrows to thrive across their range is adaptability. They can shift their preferred nest sites in response to changing habitat. If coastal shrublands are unavailable, they will readily move inland to alternative areas.
Their adaptability is evident in how golden-crowned sparrows have colonized deforested and fragmented areas. Nesting success remains high in:\p>
- Regenerating timber harvest zones
- Second-growth forest
- Areas disturbed by fire
- Coastlines altered by earthquake subsidence
This adaptability allows golden-crowned sparrows to modify nest sites and locations to match habitat changes across their range.
Conservation
Due to their large population and range, golden-crowned sparrows are not considered threatened or endangered. But some risks do impact their nesting success, including:
- Habitat loss from logging and development
- Nest predation from increasing corvid populations
- Climate change altering boreal forest ecosystems
- Brood parasitism by brown-headed cowbirds in fragmented habitats
Monitoring and conservation focused on protecting key coastal and inland nesting areas will help ensure thriving golden-crowned sparrow populations into the future.
Conclusion
In summary, golden-crowned sparrows nest across Alaska and northwestern Canada, primarily in coastal wetland habitats but also in suitable inland regions. They build sturdy cup-shaped nests 4-6 feet above ground and typically lay 3-5 eggs. Their adaptability allows them to modify nest sites to changing environments. Ongoing habitat conservation will help protect vital nesting areas for this abundant North American sparrow.