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Great Gray Owl Nesting Behavior,
Remote Monitoring Project

Volunteer Resource Page

Great Gray Cam FAQs

Coming soon!

© Daniel J. Cox/

Dear Great Gray Owl Volunteers,

Welcome! Thank you for your interest in this special project – one that runs on teamwork, volunteerism, good ‘ole fashioned observation and, most of all, amazing moments with these spectacular owls! Our nest side seat presents a rare opportunity to expand what is known about this under researched species - for personal joy and interest, as well as for research and conservation. 

We couldn’t be more excited to partner with you as we record the events of this special nest.  We know you have some questions, so here’s a brief run down: 

Who: You, we hope! This project relies on volunteer monitors to be a success. Everyone with an interest in these owls is encouraged to participate! Qualifications include: a fascination with Great Gray behavior, attention to detail, respect for wildlife research and the project, and a willingness to record events with precision.

What: A Public Participation in Scientific Research Project. Remote monitoring projects like this are made possible in partnership with, and thanks to dedicated volunteers like you!

Why: Your efforts document behaviors specific to this nest and this pair. Over time, projects like this help reveal nesting behavior norms for Great Gray Owls. Together, we will expand what is known about this species, both from a public education and scientific research perspective. After all, conservation starts with good data.  

Where: From your home! It only takes a computer and internet connection to observe and record events anytime, anywhere. This nest is in western Montana, yet viewers from around the world can watch and participate with no disruption to the owls. 

When: From incubation through fledge. 

How: Read the instructions below. This will give you all the information you need to accurately identify, and effectively record, the events you see at this nest. After you’ve done this, consider yourself part of the team!

Instructions: As you are watching the stream, look for behaviors you see on cam that correspond to the events we are monitoring for. These events are listed below. To record an event, make your selection from the survey list (link provided below) and answer the follow-up questions that appear.

Many events will ask you to reference a specific egg or chick. To determine which chick you are looking at, compare size and developmental stages. Chicks are numbered in hatching order, from the oldest (1) to the youngest (3). Keeping track of age order can be difficult, however, so if you don’t know which chick or egg it is, please do not guess! We would much rather have an entry of “unknown chick,” than have erroneous information. You can always add a note that says, for example, “the chick was one of the smaller two.”

Another section asks you to identify calls. Carefully listen to all of the examples provided below. Determining whether calls are from the male or female is difficult. Again, if you are unsure, please do not guess. You can record as unknown and do your best to describe what you heard. 

We expect to have many “unknown” entries relating to prey species, chick ages, calls, etc. This is fine! If you are unsure about something, ask for feedback in the chat. Many viewers are very experienced, knowledgeable, and helpful. We are all learning together, and this is a collaborative project in every way.


Important points to remember are:


1. Err on the side of caution. If you are unsure about a specific element of the event, please do not guess. Simply record as “unknown.”


2. Please contribute. This study relies on the volunteer assistance of cam watchers like you. We would much prefer an entry with “unknown” fields over no entry at all. This leaves an event unrecorded.


3. Familiarize yourself with the behaviors and listen to the calls before you start recording. It is important that you can easily recognize what each behavior is and what it looks like. You can watch the camera, replays, YouTube videos, or chat with other viewers to practice.

4. Record events in nest time, Mountain Daylight Time, in 24:00:00 format. We structured this survey to record the duration of each event. Some events may happen quickly, but still have a stop and a start time. You can convert your time here: Convert Time. There are many conversion tools available on-line, too. Here's a good one to Convert Time online.


There is much to be learned about these owls and the process of collaborative data collection. Your volunteer efforts expand our understanding of these spectacular owls and create new pathways for how research is conducted. We want to extend a huge thank you to for making these cams possible, and to the landowners who allow research to be conducted on their lands. And, last but not least, a million thanks to all of you for your interest and involvement! Together, we make an awesome team for owls!


To sign up for a time slot, see availability below and email Liberty at

Please note: There are two ways to access the survey page. You can access it through the link below, or through the live cam page on Here, click on the camera icon at the top of the page. Select Community Science Survey from the popup menu. Then select Go to Survey. 

Now let’s get started!

© Kurt Lindsay

K E Y   T E R M I N O L O G Y   A N D   B E H A V I O R S 

Use this guide to help understand the behaviors we are monitoring for, and what to look for when identifying events. Few Great Gray Owl behaviors are well understood or documented. Our goal is to create a record for this this nest and this pair. Over more seasons and nests, we will be able to increase our knowledge of this species. We’re including some of these known markers, however, to help you anticipate what to expect.

Prey Delivery

Owl nests employ a strict division of labor with essential contributions from both sexes. Females do 100% of the incubating; this means that she rarely leaves the nest, and usually only at night for brief periods. The male, on the other hand, does all of the hunting for the female and chicks. When he brings prey to the nest, it is called a prey delivery. During incubation, these deliveries may sometimes happen away from the nest. The pair may meet on a branch and she will accept and eat the prey off cam. As chicks hatch and food needs increase, deliveries to the nest will occur round the clock. 

Great Gray Owls are dependent on small mammals, specifically voles. These medium sized rodents will likely make up the majority of prey deliveries, however, other small mammals may be seen. Occasionally, and especially if food supplies are scarce, a bird might appear. If you see a different prey item brought to the nest, please record under 'other' and write-in what it was. Here are the four most commonly observed Great Gray prey:

I D E N T I F Y I N G  P R E Y 


Pocket gopher

This large rodent is substantially larger than a vole with a fur covered tail. It is known for it's extensive tunneling below ground - systems of tunnels and burrows from which they rarely emerge. The name pocket gopher comes from its cavernous, pocket-like cheeks which are used to transport large quantities of food back to the burrow. 

Approx. length: 7 in + 2 in tail

Approx. weight: 200 grams

During a quick prey delivery, ID by looking for noticeably large body with a short tail.

Photo © LeonardoWeiss - Own work, CC BY 3.0,



The small rodent pictured here is a deer mouse, known to invade homes and carry infectious diseases such as hantaviruses and Lyme disease. This tiny rodent likes to nest high in dead trees where they reproduce year round. They are mostly nocturnal and inhabit a wide variety of habitats.

Approx. length: 3.5 inches

Approx. weight: 20 grams

During a quick prey delivery, ID by looking for a tiny body mass, large ears, white belly, and very long tail.

Photo @ The Regents of the University of California, Deer mouse,



In western Montana there are six species of voles. Pictured above is the commonly seen meadow vole - a plump and fairly long rodent with a short tail, light belly, and gently sloping face.

Voles travel above ground through through shallow tunnels in the grass. Their populations experience dramatic peaks and valleys and, in turn, so do many vole dependent owl species. 

Approx. length: 4.5 inches

Approx. weight: 45 grams

During a prey delivery, ID by looking for a large body mass and the short tail.

Photo © Needsmoreritalin at English Wikipedia, CC BY 3.0,



Easily identified by contrasting stripes down the back, chipmunks are medium sized rodents with furry tails and upright ears. Their diet is mostly comprised of nuts, seeds, and fruits, which are also stashed and relied upon to get through the winter. Chipmunks are diurnal, or active during the day, and reproduce once a year. 

Approx. length: 7 in with tail

Approx. weight: 50 grams

During a quick prey delivery, ID by looking for conspicuous stripes and furry tail.

Photo © Phil Armitage -, Public Domain,

F E M A L E ' S  T I M E  A W A Y  F R O M  T H E  N E S T

Female Leaves Nest

Females typically only leave the nest at night. During her time away, she may receive a prey delivery, cast a pellet, defecate, or stretch. For the purposes of the survey, the time should be begin the moment she lifts her body off the eggs or chicks, and end when she flies from the nest.


Female Returns to Nest

Similarly, her return begins as soon as she lands back on the edge of the nest, and ends when she settles back on her eggs/chicks.

F E M A L E ' S  B E H A V I O R  I N  T H E  N E S T

Female Preening

Owls preen frequently in and out of the nest. Preening cleans and repositions displaced feathers which are critical to flight and temperature regulation. The female will run her beak down the length of the feather in order to smooth the surface, or sometimes appears to nibble her way down. Talons can be used to preen the head feathers. 

Female Checking / Rolling Eggs

Incubating females rotate their eggs frequently, sometimes even moving them to a new spot in the nest. Rolling the eggs ensures that the embryo gets enough albumen. This is a mixture of protein and water that makes up the 'egg white' part of an embryo. It is filled with nutrients necessary to proper development. 

Female Checking Chicks / Fussing

After chicks have hatched, the female no longer needs to roll her eggs, but will frequently check underneath her. Early on, this can be hard to distinguish from eating or feeding, but her beak will not be moving and she will be shifting chicks and nest material. 

Female Panting / Gular Fluttering

Owls do not sweat so use panting to release excess heat from the body. They sometimes pant during times of stress, as well. Panting and gular fluttering both refer to opening the mouth and puffing the throat in and out to cool off. 

Female Eating

When the male makes a food delivery to the nest which is immediately eaten by the female, record this under Prey Delivery > Who Fed > Female. If however, she caches the prey and eats it later, or returns to the nest with prey in her beak and eats it at the nest, record those events under the Female Eating category.

E G G  E V E N T S

Egg Pip

A pip is the first sign of hatching which is visible as a small piercing to the eggshell. Pipping refers to the process of breaking open the eggshell using an egg tooth - a small, sharp protuberance on the beak that is used to break through the egg’s hard surface. Strong muscles in the chick’s neck give them the strength needed to do this. Chicks initiate pipping when they are ready to survive outside of the shell and have grown too large to absorb oxygen through the pores of the eggshell. Not long after hatching, the egg tooth falls off. It may impossible to see any pips. Nonetheless, stay on the lookout and watch for behavioral changes in the female. She will hear her chick’s earliest pipping efforts and may show an increased interest in checking on the eggs, as though she is listening intently. Please only record pipping if the egg is visible.


Egg Hatch

Great Gray Owl chicks hatch after about 30 days of incubation in this area. When owl chicks hatch, they are vulnerable and helpless. They cannot walk, see, self-feed, or regulate their body temperature, and are entirely dependent on the care of their parents. They appear pink and white - the combination of exposed skin and partial down covering. Around three days in age, a chick gains the strength to lift its head. When this happens, it may offer the first glimpse of the chick. Prior to this, a hatch may only be indicated by the female’s behavior, or the sight of an eggshell. Shortly after hatching, the female will begin tearing off bits of prey and making visible feeding attempts. A chick may also be seen when she leaves the nest at night. Great Gray chicks hatch asynchronously. This means that they will hatch in the order they were laid, about two days apart.


Female Tossing Out or Eating Eggshell

After a chick fully emerges from its shell, the shell may remain in the bowl and crumble under the activity of the nest; the female may set the pieces to the side; toss them over the edge, or she may eat them. There isn’t a lot of documentation in this area, so we are anxious to record how this female handles the shells. We've created two categories - tossing and eating - but if you observe other behavior with the shells, please record it as 'other' and describe.

H A T C H L I N G   E V E N T S

Eyes Open

In general, a chicks's eyes will open around day 10. By this time, you will probably see its fuzzy white head above the nest rim or peeking out from under the mother regularly. 

Nestling Swallows Whole Prey

The female will tear off bits of prey to feed her young from hatching until they are big enough to swallow an entire vole on their own. Watch for this around three weeks.

Nestling Walking

Young Great Gray Owls won't make their first flight until they are over a month old. Even after they have left the nest, they can only get around on foot. As such, they need to start practicing early and will walk around the nest.

Nestling Stealing Prey from Other Nestling

Aggressive behavior between owl chicks is uncommon. Although that doesn't mean they won't try to steal a meal from one another!

Nestling Practicing Flight - Spreading Wings, Flapping, etc.

Wing muscles and coordination begin developing early and need exercise. Wing flapping will become a frequent occurrence and combined with walking around the nest.

Nestling Defecating

The female will keep the nest clean by eating waste until the nestlings are old enough to defecate over the edge of the nest.

Nestling Preening

As with the female, preening is an instinct that comes early and will be practiced often. The female will also preen the young, which can be recorded under this category with a note, or under 'other.'

Nestling Nest Departure / Branching

This nest is located in a tall snag with no branches, so these young owls will jump from the nest onto the forest floor around 3-4 weeks. This may sound dangerous, but they are specially made it. Their still flexible bones will absorb the fall. They young owls will set about looking for branches to climb and places to hide. And this forest - a beautifully undisturbed one - has lots of these! Parents oversee their movements and continue to make food deliveries.



While branching, young owls often make their first flight attempts. These are short and clumsy at first but around 7-14 days after leaving the nest they are capable of short flights. “Fledging’ can be defined in different ways but generally refers to the development of enough feathers to sustain flight. Flight practice takes place on the ground after running starts or from branches. For the purposes of our study, fledging is defined as a flight that has both a coordinated takeoff and landing. Hopping up and down, or flights with crash landings are practice runs and not to be considered ‘fledging.’ It is unknown if we will be able to observe these first flights or not.

Male Feeding Nestling

Around 2-3 weeks the female will begin roosting outside of the nest, but close-by. The male will continue delivering food to the female and she will feed the young. After the young owls leave the nest, and around 3-6 weeks, the female will leave her young. At this point the male will takeover all feeding and care, up to three months.

Species account / breeding behavior cited:

Cornell Lab of Ornithology, Birds of the World

Great Gray Owl, Stix nebulosa

Evelyn L. Bull and James R. Duncan
Version: 1.0 — Published March 4, 2020



A female Great Gray will lay 2 - 5 eggs, depending on prey availability. Incubation is 28 - 36 days, with 30 typical for this area.

Eggs average:

Width approx: 43 mm or 1.69 in

Length approx: 54 mm or 2.12 in

Photo © Klaus Rassinger und Gerhard Cammerer, Museum Wiesbaden - Own work, CC BY-SA 3.0,



An egg pip as seen on an eagle egg at explore's Sauces nest.

Photo ©

Kingston's Owl Centre.jpg


A newly hatched Great Horned Owl chick. The appearance is very similar to a Great Gray chick.

Photo © Kingston Owl Center, UK


Disposing of eggshells

2017 EF nest female eating the eggshell after a hatch.

Photo ©

2020 cam male at Jim's Place hunting voles in a meadow near the nest.

G R E A T  G R A Y  C A L L S  &  V O C A L I Z A T I O N S

Following are the vocalizations listed in the survey. Please listen carefully to each before recording in the survey.

Unless credited, these audio files are from the 2017 EF Great Gray nest. We recommend listening with headphones and turning your volume up.

Female Food Begging CallGreat Gray Owl
00:00 / 00:22

Female food begging call -

A squeak like call, generally when she is hungry, and gets louder when the male is nearby with food. These calls are often given in a repetitive sequence, for extended periods of time. When recording, you can enter them individually, or time the spacing and record them as, for example:

Start: 07:12:05  End: 07:13:15

Notes: call given approx every 5 seconds during this time.

Female Gwuk CallGreat Gray Owl
00:00 / 00:14

Female Gwuk Call - 

Louder and more bark-like than the begging call, generally only repeated a few times before, during and just after food deliveries.

Female Defensive Hoot 1Great Gray Owl
00:00 / 00:11
Female Defensive Hoot 2Great Gray Owl
00:00 / 00:13

© Cornell Lab of Ornithology

Female defensive hoots - 

A repeated low pitched call that has a slight tremor to it, generally given in response to a possible threat near the nest, or in response to the male territorial hoots. She can also give a more territorial call that has no tremor, single note repeated, slightly higher pitched than the male.

Female Agitated HootGreat Gray Owl
00:00 / 00:16

© Cornell Lab of Ornithology

Female agitated hoots - 

A higher pitched, lilty call generally heard in response to an a stress or agitation in the area.

Male Territorial HootGreat Gray Owl
00:00 / 00:45

© Cornell Lab of Ornithology

Male territorial hoots - 

Very low pitched, repeated deep hooting call, generally used as territorial. The male will give three similar hoots as a contact call to the female.

Male Chitter Contact CallGreat Gray Owl
00:00 / 00:11
Female Chitter Contact CallGreat Gray Owl
00:00 / 00:07

Chitter contact call - 

A chattering, trilling call generally heard during food deliveries. The male often starts the chitter call as he approaches the nest. The female begins her chitter call when he comes in with food. She also uses a softer chitter call when she is feeding the young.

Chick Food Begging CallGreat Gray Owl
00:00 / 00:56

Chick food begging call - 

A little, high pitched squeak or shriek that gets louder and more consistent as the chick ages.

O T H E R  E V E N T S  A T  T H E  N E S T

Predator at Nest

Almost all eggs and young chicks are vulnerable to predators. This natural nest is located in an area shared with mesopredators like coyotes, foxes, raccoons and skunks; where bears, and occasionally wolves pass through; and where eagles, hawks, and other owls are common. When confronting a threat or predator, owls demonstrate a variety of nest defense strategies: bark-like hoots, distraction displays, or by diving at the threat. It varies among species and between individuals. All of these behaviors are survival strategies. When watching owl live cams, please remember that these are wild animals in nature. Events that occur on cam can be hard to watch sometimes. At the Owl Research Institute, we have a non-intervention policy. Please review this below.


Other - Write in

When conducting research, standardized categories and methods of data collection are imperative to the process and results. But these are just part of the picture. Unforeseen and surprising events will always happen. As such, please make note of events of special interest.

I N T E R V E N T I O N  P O L I C Y

The opportunity to be immersed in the lives of wild creatures makes it easy to become emotionally invested in their well-being. This connection is one of the most powerful things about wildlife cameras, but it also makes them difficult to watch sometimes.


At the Owl Research Institute (ORI), our approach to research and monitoring, including situations that occur on camera, aims to reveal and document how natural processes unfold. These are wild animals and we've made a conscious decision to keep ourselves out their lives as much as possible. While immediate intervention might sometimes seem like the appropriate response, it’s important to remember that we often don't have the right answer. There are countless instances of human intervention which have not solved the problem at hand, and in fact, created a whole host of other unintended consequences.


At ORI, we have a non-intervention policy. Exceptions include situations caused by humans. We have, for example, removed fishing line from the beak of an Osprey chick. A chick that is not thriving, however, would not warrant intervention of any kind. Decisions involving a bird in distress often need to be made quickly, with the information at hand. 


Sometimes it isn’t entirely clear what is going on and gray areas exist. We will assess, and respond, to each situation as it arises. Like you, we want to see the birds thrive. But, as researchers and cam watchers, our role is not to influence the natural interactions between species and their environments. It is to learn, enjoy, document, and promote the conservation of these animals and their ecosystems. 


Thank you for your interest and participation in this project!

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