Where is this nest located?

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The Owl Research Institute brings you both Great Gray nests from western Montana. The Jim’s Place (JP) cam is located in the Mission Valley, the Great Gray nest cam is located in the Flathead Valley. The JP nest is the only active nest this season.

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The habitat is coniferous forests adjoining meadows and seasonal bogs and/or creeks. Both nests are housed within dead trees, commonly known as snags. When the top of a tree breaks off, over time, a smooth bottom forms. This flat-bottomed bowl collects forest material like pine needles, leaves, and sawdust like shavings from the tree itself. Often the sides remain, creating a semi-enclosed nest for large birds like Great Gray Owls. These owls will also nest in the abandoned stick nests of other large boreal forest birds, although all our cam-nests have been housed in snags.

These dead trees don’t remain standing forever and serve important roles in forest ecosystems when standing, and after they have fallen and lay on the ground. In 2018, after the owls had left the nest at JP, the entire snag fell over. We cut off the nest portion of the tree and mounted it to a platform nearby, preserving it as a nesting option for the owls. In 2019 and 2020 they made short visits to the nest but have not chosen it as a nesting location since nesting in it in 2018.

 

Do the owls use the same nest each year?

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Great Gray Owls will often return to the same snag year after year. In the case of our cam-nests, however, this has not been the case. In 2017, a pair nested in the EF snag hatched four eggs and fledged three chicks, but none have not nested in that location since. In 2018, a pair nested in the JP snag and hatched one chick from two eggs, but fledged no chicks. They have not returned to nest in that location (albeit an altered one given our actions after the snag fell).

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Because owls do not build or repair their own nests, sometimes a nest will break down to a degree that it is no longer usable. This is more common with stick nests, but all snags will eventually fall. Some believe that owls are less likely to reuse a nest after an unsuccessful year. Some areas have few nest options, which might force the owls to reuse the same nest year after year. Whatever the reasons, the owls sometimes reuse a nest, sometimes they don’t.

 

Do the owls mate for life?

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Great Grays are monogamous and it is believed that pairs probably mate for life. If one of the pair disappears, or dies, either of the remaining sex will seek a new mate. Members of a pair often remain on the same territory year-round, though may not maintain their pair bond through the winter.

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How many eggs to Great Gray Owls lay?

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Females lay 2-5 eggs, depending on food availability. Eggs will hatch in the order they were laid, about every other day.

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When were the eggs laid?

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March 29th is our first record of the female settled on the nest. During courtship, both the male and female visit potential nest sites for several weeks before selecting a nest. We knew that this pair were visiting the 2020 nest site and both were seen roosting and courting nearby.

We don’t know if the female laid her first egg on March 29th, but owls do not spend much time on the nest before this. This date should be close.

Great Grays generally have only one brood per season. Second broods have been reported after a first failed attempt but are rare.

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How long does it take for the eggs to hatch?

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Females begin incubating the first egg as soon as it is laid, and it will hatch in 28 – 36 days, with 30 most common in this part of the world. She will lay another about every other day. The eggs will hatch asynchronously, in the order they were laid, over a period of several days.

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What do the eggs look like?

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A first glance, Great Gray eggs look similar to a chicken egg you’d buy from the grocery store. Upon closer inspection, however, they are not as bright white and rounder than a standard chicken egg.

Unlike many wild birds, owl eggs are not speckled or camouflaged, they are just plain white. White eggs are commonly attributed to species who are cavity nesters (why camouflage your eggs when they’re inside a cavity?), but owl species who nest in open nests, like Great Grays – also have white eggs. So do most ground nesting species. Denver Holt believes this is because they’re nocturnal. During the day, when camouflage would be needed, female owls rarely leave the nest. When she leaves the nest at night to defecate, cast a pellet, or receive prey, fewer predators are active and the eggs are not visible to many animals. Those who are, would see them whether they are camouflaged or not.

 

No one is sitting on the eggs or young. Won’t they get cold?

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Great Grays are a Northern owl and cold temperatures, especially at night, are common when they begin nesting in late March to early April in western Montana. These large owls are well adapted to withstand such conditions, as are their eggs and chicks.

It is normal for an incubating female to leave the nest for short periods at night, leaving her eggs and/or chicks exposed. Records exist of owl eggs remaining viable after extended periods of time, up to 20 minutes, in below zero conditions. Longer periods off the nest may result in the chicks shivering, but they warm up and return to normal shortly after her return. Under normal circumstances, the female will not leave the nest beyond what the eggs and chicks can tolerate.

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Do the eggs ever get damaged and what happens if they do?

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Yes, eggs can be damaged for a variety of reasons, including an accidental nick by the female’s talon. Sometimes the eggs will go on to hatch, sometimes they will not.  

When the embryo itself fails to develop, the egg is considered non-viable. This can happen for a variety of reasons and the female may respond in different ways. Sometimes she will pitch the egg out of the nest. Sometimes she will continue to incubate it, even surpassing normal ranges for hatching. When this happens, it is called prolonged incubation. We observed this at the 2018 Jim’s Place nest when the female incubated one non-viable egg a month beyond its estimated hatch date.

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There are both eggs and chicks in the nest. Is there something wrong with those eggs?

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Probably not. While an egg can be non-viable, it’s more likely that what you’re seeing is completely normal. All birds lay eggs asynchronously, or not at the same time, and usually every other day (it takes at least 24 hours for the egg formation process to take place within a bird). Some birds, like owls, start incubating their first egg from the moment it hatches. Some birds delay incubation until all the eggs have been laid. These eggs will hatch synchronously, or at the same time. Conversely, owl eggs hatch asynchronously, in the order they were laid. The result is a nest containing chicks of different ages or, in the hatching stages, a nest containing both eggs and chicks.