| Nesting Activities |
Bluebirds |
Tree Swallows |
House Wrens |
House Sparrows |
Dates:
(1) |
Earliest Arrival |
So MN: 2-27, No MN: 3-6 |
So MN: 3-12,
No MN: 3-22 |
So MN: 3-30,
No MN: 3-30 |
Permanent resident |
| Peak Arrival |
Mid to late March |
Mid to late April |
Early May |
Permanent resident |
| Breeding Season (2) |
Mid to late April |
Mid may |
Late May |
Permanent resident |
| Peak Departure |
Late Sept. to late Oct. |
August & September |
Early September |
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 |
Open woodland & 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) (3) |
Curved white feathers |
Twigs with spider egg
cases (3) |
Grass or by sitting in
hole (4) |
| Materials |
Dry grass & 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 & shape |
Loosely built with 2-3" cup |
Loosely woven with large
shallow cup, feathers
upright 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 (5) |
4-11 days usually by F, -M
(2-14 days possible) +
possibly 1+ week before
first egg laid |
14-21 days usually, by F
(7-30 days possible) |
M: 8-10 days (base) +
F: 4 days (lining) +
possibly 2 days before 1st
egg laid |
1+ days, by M, -F |
| Eggs: |
Color (size) |
Blue to white, somewhat
glossy (21x16mm) |
White, slightly glossy to
non-glossy (19x13mm) |
Light pink to white with
rust specks (16x12mm) |
Off-white to bluish green w/
gray brown spots (23x16mm) |
| Total number laid |
4-6 eggs (3-7 possible) |
5-6 eggs (4-8 possible) |
5-8 eggs (to 12 possible) |
4-6 eggs (3-8 possible) |
| Incubation period |
12-14 days
(12-18 days possible) |
14-15 days
(13-16 days possible) |
13 days
(12-15 days possible) |
12 days
(10-14 possible) |
| Hatch timing |
Synchronous |
Synchronous (or partially
asynchronous)? |
Synchronous |
Synchronous |
DO NOT DISTURB after: (Age when
nestlings could prematurely fledge) |
12 days |
15 days |
9 days |
Remove eggs before they
hatch!! |
| Total time in Nest: |
17-18 days usually
(15-20 is possible) |
20-21 days usually
(16-24 possible) |
16-17 days usually
(12-18 possible) |
15-16 days usually
(14-17 possible) |
| Number of Broods: |
2 broods (sometimes 3) |
1 brood (rarely 2) |
1-2 broods (rarely 3) |
2-3 broods (sometimes 4) |
