Nesting Activities |
Bluebirds |
Tree Swallows |
House Wrens |
House Sparrows |
|
Dates |
Earliest arrival | First week in March | Last week in March | Late April | Permanent Resident |
| Peak arrival | Mid to late March | Mid to late April | Early May | Permanent Resident | |
| Breeding season | Mid to late April | Mid May | Late May | Late April to early May | |
| Peak departure | Late Sept. to early Nov. | July and Aug. | Early Sept. | Permanent Resident | |
Nest Building |
Location of nest (in natural cavities) | Open country with scattered trees to wood borders, near mowed or sparsely covered ground Partly open country with old or dead trees, often near water | Partly open country with old or dead trees, often near water | Open woodland and wood borders, shrubland, farmland, suburbs, up to 200′ from cover | Hole or crevice anywhere, especially by buildings |
| Male claims nest with: | Grass (1-6 weeks before nest building) | Curved white feathers | Twigs with spider egg cases | Grass or sitting in hole | |
| Materials | Dry grass and weed stems, pine needles (occasionally fine rootlets or twigs), lined with finer grass (occas, hair or feathers) | Dry grasses (occasionally straw, cattails or pine needles), lined with feathers (often white) | Twigs with spider egg cases (occasionally stems, leaves, fibers), lined with fine grass, feathers, hair, bark strips | Long coarse grass stems with seed heads, weeds, feathers, trash | |
| Size and Shape | Loosely built with 2-3″ cup | Loosely woven with large, shallow cup, feathers uprights curving over eggs | Bulky base of twigs (nearly filling box) with small deep cup at top rear | Large untidy dome with side entrance to deep space with little or no bottom | |
| Days to build and builder | 4-11 days usually (2-14 days possible) by female usually; can be up to 1 week before 1st egg is laid | 14-21 days usually (7-30 days possible) by female | 8-10 days for male to build base; 4 days for female to line; can be up to 2 days before 1st egg is laid | Can be built in 1 day, usually by male | |
Eggs |
Color/Size | Blue to white, somewhat glossy | White, slightly glossy to non-glossy | Light pink to white with rust specks | Off-white to bluish-green with gray/brown spots |
| Total number laid | 4-6 eggs (3-7 possible) | 5-6 eggs (4-8 possible) | 5-8 eggs (up to 12 possible) | 4-6 eggs (3-8 possible) | |
| Incubation period | 12-14 days (12-18 possible) | 14-15 days (13-16 possible) | 13 days (12-15 possible) | 12 days (10-14 possible) | |
| Hatch timing | Approximately same time | Approximately same time | Approximately same time | Approximately same time | |
|
Do Not Disturb (age when nestlings could prematurely fledge) |
12 days | 15 days | 9 days | Remove eggs before they hatch | |
| Total time in nest | 17-18 days (15-20 possible) | 20-21 days (16-24 days possible) | 16-17 days (12-18 possible) | 15-16 days (14-17 possible) | |
| Number of broods | 2 broods sometimes 3 | 1 brood (rarely 2) | 1-2 broods (rarely 3) | 2-3 broods (sometimes 4) |