What Outcome Code Should I Choose?
When you are summarizing and ending a nest attempt, you will be asked to record the outcome of your nest, or the “Nest Fate.” The Nest Fate dropdown will give you several options to choose from.
If at least one of the host young successfully fledged the nest, select the “At least one host young fledged” option. You can choose this option even if some of your eggs or nestlings did not survive. As long as at least one did, the nest is considered successful.
If your nest was not successful, meaning that no young fledged the nest at all, then you have several options to choose from:
All young found dead in or nearby nest – choose this when you find nestlings dead in the nest or on the ground beneath the nest.
All young disappeared from the nest before the expected fledge date, reason unknown – choose this when you have nestlings that disappear before the fledge date but you aren’t able to determine the reason why.
Predator known to cause nest failure – this option is for when you know a snake, raccoon, chipmunk, or other predator depredated your nest. This is also the option to choose when you visit your nest and suddenly find all eggs missing without a trace, or if you find nest materials partially pulled out of a nest box entrance hole. These are signs that a predator visited.
Only cowbirds fledged – if your nest had cowbirds or other brood parasites in the nest along with the host eggs/young, but only the cowbirds survived to fledging, choose this option.
Invasive species management. This option should be used when you are reporting an invasive species nest, and you took legal management actions that caused the nest to fail. For example, in North America, House Sparrows and European Starlings are invasive species, and some monitors choose to manage those populations by removing nests, eggs, or young before they fledge. Learn more about invasive species nest management techniques.
No eggs hatched – choose this if the clutch of eggs never hatches, and they remain in the nest well after the expected hatch date. Do not choose this if eggs disappear from the nest prematurely – disappearing eggs are almost always due to a predator.
Failure due to nest takeover by another bird – this is used when a bird interrupts the nest of another bird and then takes over that nest site for themselves. For example, House Sparrows and House Wrens will commonly take over a nest site and build their own nest right on top of the in-progress one. In that case, you would choose this option when you summarize the first bird’s nest. Then, add a new attempt to report on the new bird’s nest as normal. Other birds may engage in this behavior too, such as a Tree Swallow taking over an Eastern Bluebird nest, or vice versa. You will have the option to enter the species that took over, if you know it.
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We prefer you to choose a success or fail code if you know it, but there are also two options you can choose if the outcome is truly unknown. If your nest is active, but you need to stop monitoring the nest before the fledge date, and then afterwards are unable to determine whether the nest was successful, please choose Nest monitoring stopped prior to expected fledge date while nest was still active.
If your nest was active, but you don’t know whether young fledged and have no clues to help you, choose Unknown Outcome.
Finally, if you visited a nest all season and there were no eggs or young in the nest at all, please choose No breeding behavior observed. While nest building is technically a breeding activity, if no eggs are ever laid in a nest that was built, this is still considered to be “no breeding behavior observed” in NestWatch.