the Nest Files – Red-winged Blackbird

adult male Red-winged Blackbird (Derbyshire)


Red-winged Blackbird (Agelaius phoeniceus)

Nidiologicals – Peck and James (1987) and Yasukawa and Searcy (1995)

Habitat – Highly variable. Marshes, wetlands, fields, pastures and open woodlands.
Microhabitat – Nest usually woven into vertical shoots of a wide variety of substrates; commonly built within 1m of ground.
Spring arrival – March (Ontario)
Average nest height – .1m to 1.4m
Nest builder – female
Average # of broods/season – 1.7
Average egg laying date – 26 May-13 June (Ontario)
Average clutch size – 4 eggs
Incubation period – average 12.6 days
Egg colour – light blue-green or gray, marked with streaks, blotches and specks of black or brown. Markings are water soluble and fade during incubation (Nero 1984).
Incubation – female
Fledgling stage – young leave nest 10-12 days after hatching.
Parasitized by cowbirds – yes


Red-winged Blackbird nest contents


The Red-winged Blackbird is one of the most abundant and frequently studied bird species in North America. They are temperate migrants, returning to Ontario in early spring when males establish or reestablish territories in a wide variety of open habitats in upland and lowland environments. Red-wings breed across a vast range from boreal Alaska to Costa Rica. This range encompasses a considerable diversity of climatic and ecological conditions, which has certainly contributed to the total of twenty-six subspecies having been identified. Even more compelling is their complex social system. Up to fifteen females have been found to nest in the territory of a single male – making them one of the most highly polygynous of all bird species!


The nest pictured above was discovered in a medium sized palustrine marsh on Big Salmon Lake. The marsh was dominated by flooded grass and shrub growth as well as lesser quantities of cattail. Large numbers of Red-winged Blackbirds were present along with Swamp Sparrows, Yellow Warblers and Common Yellowthroats to name a few. The nest was located by accidentally flushing an incubating female. Given their abundant colonial populations, preference for open habitats and non-cryptic nature, it is not surprising that nests of this species are so frequently reported to nest record schemes. I was excited to find this one – a first for FBS. Red-winged Blackbirds can be found regularly in Frontenac Provincial Park but they occur in relatively small, isolated pockets where cattail and shrub cover is suitable.


Nest site


This last photo paints a picture of the nest site context (note the circled tuft of grass/shrub). The male held court over this section of the wetland while other occupied territories were being defended nearby. We don’t have waterbirds or wetlands as priorities for our studies at the moment but I expect we will turn our attention to these important areas in the future. Currently we are focused on species & habitats of conservation concern but we are fundamentally interested in keeping common birds common, such as the iconic spring harbinger – the Red-winged Blackbird.

2 thoughts on “the Nest Files – Red-winged Blackbird

  1. Nice pecs!

    I’m helping with nest searching here and we are finding similar nest sites. It is very cool to peer in and see a future family.

    Notably, the invasive phragmites is passed over by the Red-wings and they are only using bulrushes. I sure hope you do not see any phragmites in your park!!!

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