9. Breeding Biology

Who builds nests and how long does it take

Who buildss nests?  

Females, males, bi-parental 

How long does it take to build a nest? 

Species varies with 

 • the complexity of the nest  

• time of year  

• weather In temperate areas, construction of the first nest of the breeding season may take longer than nests later in the season  

Generally, passerines build nests over a period of a few days 

Time needed for representative songbirds to complete their open-cup nests.

Time needed for representative woodpeckers to create nest cavities.

 

Construction of the nests of some larger birds, such as raptors, may require as long as several weeks.  

Woodpeckers excavate nest cavities in tree trunks or branches, a process that, for species found in North America, typically takes anywhere from 6 to 36 days 

What is purpose of nests?  

To provide a receptacle in which birds can lay their eggs and/or raise their chicks-- -protect them from predators  

-shelter, temperature regulation  

Nests provide protection from predators (avian and terrestrial)  

a) Concealed - Cryptic and difficult to see.  

- parents are surreptitious “sneak” back to nest when providing care, use indirect routes; females are cryptically coloured to blend in while incubating or brooding. 

 b) Inaccessible: built off the ground, away from terrestrial predators. 

-cliffs, trees, caves 

c) Impregnable : enclosed, cavity, or suspended   

 

Insulation - 

line the nests with materials that provide good insulation. R 

egulate nest microclimate (grasses, feathers, fur, fungus)  

e.g. Bicknell’s Thrush  -Horse-hair fungus   

 

Black-capped Chickadee -gathering hair to use to build its nest 

 

Tree Swallow - feathers 

Nests help maintain a constant thermal environment and prevent overheating. 

Nest location and orientation impact microclimate - diurnal and seasonal  

Nests help maintain a constant environment and prevent overheating.  

For instance, some species select nest sites to mitigate environmental factors such as heat and solar radiation.  

Many songbird nests are oriented so that vegetation provides shade in the afternoon when the temperatures are higher, while not blocking sun in the morning.  

White-crowned Sparrow nest.

Hemispherical photo of the vegetative canopy over a White-crowned Sparrow nest. Nests often have less vegetative cover in the eastern sky, allowing more solar radiation to strike nests in the morning when ambient temperatures are cooler and reducing likelihood of overheating during warmer afternoon (From: Walsberg and King 1978).   

common Grackle

Common Grackle The lip of the open cup nest, like that shown here, may also cast a shadow within the nest cup during certain times of the day. 

Wetland nesting population  

Clutch size: 2 to 7 (typically 4 or 5)  

Fledge: d12-15  

Study site: Cape Breton 

Shade seeking by common Grackle nestlings at the scale of the nanoclimate. Context-dependent costs and constraints of begging and non-begging activity by comon grackle nestlings at the scale of the nanoclimate. THESE ARE BOTH THE TITLES OF ARTICLES ON THE SLIDESHOW 

STABLE THERMAL ENVIRONMENT

STABLE THERMAL ENVIRONMENT ,Growth, Survival (hyperthermia) 

A stable thermal environment is needed to maintain coordinated activity. This has implications for food acquisition since nestlings need to beg to get food.  

HIGH BODY TEMPERATURE INFLUENCES DIGESTION AND MOTOR-SKILL PERFORMANCE, INCLUDING BEGGING.  

The thermal environment of the open cup nest  

The thermal environment of the open cup nest  

Nests can be heterogeneous environments: when it is hot, shade can be an important resource

Thermal Environment	Temp (degC)	Solar radiation (Wm^-2)
Shade	27.6	138.9
Sun	38.4	862.9
Paired t-test	<0.001	<0.001

Grackle nestlings and shade

Grackle nestlings prefer shade  

11 nestling pairs – trials lasted 15 minutes 

 Where did nestlings go when in nest with heterogeneous vs. homogenous environments ? Nestlings in heterogeneous environment moved to the shade. 

Heterogeneous (half shade?) Homogeneous (all sun?) 

 

Grackle nestlings benefit from shade  

Increase in body temperature reduced when nestlings able to access shade 

 Rate of ∆: F1,51=7.99, P = 0.007 

 

Table 1. The duration (min) of behavioural response by nestlings exposed to heterogeneous and homogeneous nest cup environments. n=11 BARBS TABLE...her research? 

Measuring energetic cost 

An environmental chamber maintains thermoneutral conditions  32˚C - 34˚C 

- A solar illuminator generates three intensities of solar radiation 

 <2 Wm-2  (room light)     500 Wm-2   (shade in nest cup      1000 Wm-2  (sun in nest cup) 

Respirometry equipment measures oxygen consumption and carbon dioxide production 

 Converted to a measure of energy consumption  

Presented as metabolic scope: AMR/RMR 

Design of lab studies 

Room light:RMR, shade: AMR, Sun: AMR 

RMR=no solar radiation, no stimulation, unfed 

AMRb=begging activity 

AMRnb=nonbegging activity 

 

cost of begging and cost of non begging

	Cost of non-begging activity AMRnb:RMR	Cost of begging activity AMRb:RMR
Shade	1.05	1.03
Sun	1.10	1.09

Cost of being in the sun to a nestling

Cost of being in the sun to a nestling 

Support for context dependence  

Both begging and non-begging activity are more costly in the sun than in the shade 

Which leads to behavioural constraints 

The e time a chick can spend begging falls when they are exposed to the sun, potentially affecting feeding success 

Grackle nestlings respond to sun exposure by seeking the shade, which helps to reduce body temperature and energy expenditure 

Nest Types  

Types of Nests– refer to text for details  

A)Simple cup nest e.g. passerines and hummingbirds, american robin) 

B)Domed nests e.g. wrens, magpies, Eastern Meadowlark  

C)Suspended (pensile, pendulous) e.g., orioles 

D) Adherent nests- cupped nests whose sides are attached by an adhesive substance (e.g., mud or saliva) to a vertical surface, like those of swifts and some swallows e) f) Floating nests e.g. waterbirds  

Tree holes (cavity nests) 

 •primary cavity nesters e.g., woodpeckers  

•secondary cavity nesters e.g., some chickadees, bluebirds 

 g) Burrows Bank Swallow, Belted Kingfisher, Burrowing Owl, Leaches Storm Petrel, Atlantic Puffin  

h) Simple scrape nests e.g. shorebirds, gulls, terns, nighthawks, vultures 

Ruby-throated hummingbird 

 The Ruby-throated Hummingbird is the only hummingbird species that breeds in Eastern Canada, including Cape Breton.  

The female builds a nest from plant fibers held together with spider silk and covers (conceals) the nest with lichen or moss.  

 

Platform nests, Suspended cupped nest, Domed nest, AND aDHERENT NEST

Platform nests- bald eagle, osprey, great blue heron, most dove species 

Suspended cupped nest 

s- nests not supported from below but from the rims, sides, or both:  

Pensile nests - suspended from the rims and sides; rather stiff cup e.g. kinglets, vireos Pendulous - nests suspended from the rims and sides; flexible and deep cup e.g. orioles  

Domed nest- ground-nesting species eg Eastern Meadowlark and Ovenbird 

 Adherent nest:  

-treeswift species, 

- cliff swallow and Barn Swallow(adherent mud nest) fortress of louisbourg, resident population 

Cavity nesters 

primary cavity-nesters-excavate cavity  

• E.g. woodpeckers, Red breasted and White-breasted Nuthatches  

secondary cavity-nesters  

•-use abandoned cavities  

• e.g. Eastern Bluebirds, Tree Swallows, some owls  

Woodpeckers excavate nest cavities in tree trunks or branches, a process that, for species found in North America, typically takes anywhere from 6 to 36 day 

European starling, house sparrow 

Burrow , scrape nests, no nest, vegetation raft nest

Burrow- Excavate eg kingfishers 

 

Scrape nests- killdeer,ladder-tailed nightjar 

 

No nest! e.g. White Tern Lays its eggs on branch. Raises its own young (not a brood parasite)  

Vegetation raft nest- grebes and other aquatic species like Black Tern 

 

Does not build own nest  

Does not build own nest  

Brown-headed Cowbird 

 Obligate, generalist brood parasite 

 • lays its eggs in the nest of many different species  

• relies upon unrelated host parents to care for offspring  

Nest Building and Design 

Nest Building and Design 

Nests are complex and diverse.  

Birds use a wide varietyof natural materials to build their nests, including feathers, fur, leaves, pine needles, twigs, mud and spidersilk.  

The design of nests is influenced by a variety of factors.   

Nest building 

Nest building 

 Nest building is primarily instinctive. Two lines of evidence support this:  

a) the structure and composition of nests exhibit little intraspecific variation  

b) birds raised in isolation tend to build species-specific nests  

Evidence also indicates that birds learn by experience.  

Left, nest built by older, experienced male Village Weaver and, right, the first nest built by a young male (Collias and Collias 1964).   

 Some birds incorporate plants

 Some birds incorporate plants to inhibit bacterial growth and deter ectoparasites such as mites. 

 e.g. Blue Tits use and regularly replace lavender, yarrow, curry, mint - plants with chemicals that may deter bacteria, fungi and insects while nestlings present. 

 e.g. European Starlings – incorporate nettle and yarrow, pungent plants that contain chemical compounds that inhibit bacterial growth and blood-sucking mites  

Anthropogenic nest material 

Anthropogenic nest material 

Why do birds incorporate anthropogenic materials in their nests? 

 1.availability– increased anthropogenic material/reduced natural material in nest construction Assumption: birds will use most available material  

2. age e.g. older, more experienced Black Kite individuals more likely to include anthropogenic materials – extended phenotype, signals builder quality 

 3. adaptive/functional hypothesis - links incorporation of anthropogenic material to potential reproductive benefits – can therefore be considered an extended phenotype.  

NOTE: clear links between individual nest-building behaviour using anthropogenic material and individual fitness are scare. 

NOTE: clear links between individual nest-building behaviour using anthropogenic material and individual fitness are scare. 

 e.g. cigarette butts may repel ecto-parasites or reinforce structure of nest…but evidence of  

e.g. plastic string may reinforce nest structure The adaptive potential of the inclusion of anthropogenic nest materials, viewed as a trait in the extended phenotype concept, remains poorly understood.   

Article titled: The extended avian urban phenotype: anthropogenic solid wast pollution, nest design, and fitness 

 

Nests as extended phenotypes of the individual building it 

- “non-bodily characteristic” 

- signaling function (display, information) as opposed to insulation 

- adaptive (enhances fitness) Black Kite 

Black Kite 

Black Kites that use the most white plastic to decorate their nests are better fighters and produce more offspring. . 

The decorations signal a reliable threat to conspecifics.  

Older and more experienced individuals are more likely to incorporate anthropogenic materials into their nests 

 Anthropogenic nest materials likely serve as an extended phenotype and sexual signal expressing builder quality. 

Article called Raptor Nest Decorations Are a Reliable Threat Against Conspecifics 

Plastic debris

Plastic debris has been incorporated into the nests of some seabirds 

 A lot of research in this area.  

What about urban birds? 

 

Urban nest sites : PICTURE AND FIGURE CAPTION SLIDE 56 

 

Nest Substrates used by urban birds 

ADD INFO FROM SLIDE 57 

 

Some urban birds incorporateman-made materia

Some urban birds incorporateman-made material, including garbage (e.g. cigarette butts, ribbon, foil, paper, plastic, twine) Fig. 1. Song thrush nest and eggs (1 manipulated and 2 control) from which nest background and cigarette reflectance measurements were taken. White arrows indicate the positions of the three cigarette butts incorporated into interior nest matrix. Photo credit: Mark Hauber- Structural elements 

fibres from cigarette butts are being found in bird nests

fibres from cigarette butts are being found in bird nests. E.g. House Finch- 

-  nicotine in fibers may deter ectoparasites 

 BUTat a cost of genotoxic damage (abnormalities) to chicks and adults  

Figure caption: . An increasing number of humans ….

Figure caption: . An increasing number of humans are moving into cities, driving urban areas to expand in size. We demonstratethat human presence and urbanisation(modelled as impervious surfaces), assessed at a fine spatial scale, significantly covary with solid waste pollution in the environment. Moreover, we demonstrate a positive relationship between human-driven environmental solid waste pollution and the contribution of anthropogenic nest materials in great tit nest design. Importantly, we also report on a clear, negative relationship between anthropogenic nest materials (nest design) and blue tit reproductive success. Green and red arrows report on significant positive and negative relationships demonstrated in this study, respectively. The black arrow reflects the positive relationship between human presence and urbanisation as reported 

ig. 2. Ground environmental solid waste pollution

Fig. 2. Ground environmental solid waste pollution in contrasted levels of human presence and Impervious Surface Area (ISA) (Transect Data). Total number of solid waste items detected in the environment by surveying ground transects and grouped by contrasted levels of Human presence (a) and Impervious Surface Area (b), N = 100 nestboxes, corresponding to 300 ground transects. Low (mean ± se, 0.29 ± 0.03) and high (2.18 ± 0.23) levels of human presence included each 50 nestboxes. Low (mean ± se, 1.03 ± 0.2) and high (mean ± se, 24.7 ± 2.25) levels of ISA, included 50 nestboxes.  

blue tit

Blue Tit – anthropogenic nest material  found cigarette filter (paper), clothing (cloth), threat (cloth), plastic string (plastic) 

Blue Tit – impact of anthropogenic nest material on reproductive success  

Fig. 5. Blue tit reproductive success decreases with increasing proportion of anthropogenic material in the nest (Nest Data). The prediction of increasing proportion of anthropogenic nest materials in nest on number of hatchlings (a) and fledglings (b) of blue tit. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)  

highlights

Highlights 

-Human presence and urbanisation positively covary with solid waste pollution 

-urban solid waste pollution covaries with solid waste in great tit nests. 

-The more anthropogenic materials in nests, the less fur and feathers    Sugessts birds replase natural material with waste material 

Anthropogenic nest materials negatively covary with blue tit breeding success But not Great Tit breeding success. Suggests species specific vulnerability 

Birds around the world are building their nests with trash: heres how we can move towards protection 

Birds around the world are building their nests with trash: heres how we can move towards protection 

-176 bird species on all continents except antarctica have been found to use trash in their nests 

-This trash can harm birds and their chicks, as it can entangle them, block their airways, or even poison them 

-it is important to be aware of the dangers of trash in bird nests so that we can take steps to protect these amazing creatures 

-Some bird species, such as blackbirds and storks, are more likely to use trash in their nests than others 

TOOLS FOR IDENTIFYING NESTS

TOOLS FOR IDENTIFYING NESTS What’s in your neighbourhood?  

• LEARN FOCAL SPECIES  

• LEARN WHERE NESTS ARE LOCATED (THIS IS A GREAT SEASON TO LOCATE NESTS!  

• WATCH FOR NESTING BIRDS IN THE SPRING  

 

TOOLS FOR IDENTIFYING NESTING BIRDS…AND THEIR NESTS article...