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Peregrine Survey Protocol
A Protocol for Surveying Nesting Peregrine Falcons
Geographic Regions
For the purpose of presenting consistent data, we divide California into the six geographic regions defined by Herman, et. al., in 1970. Unique numbers are assigned to nest sites by SCPBRG staff along with a common name within each geographic region.
The six regions are:
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North Coast (NC): From the Oregon border (42° N latitude) south to the entrance to San Francisco Bay.
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Mid-Coast (MC): From the entrance to San Francisco Bay south to 34° N, very near the line separating Ventura and Los Angeles Counties, and including the Channel Islands.
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South Coast (SC): From 34° N south to the Mexican border.
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North Interior (NI): All areas inland (not coastal) south of the Oregon border and north of 38° N latitude, and east to 2000 feet elevation on the west side of the Sierra Nevada; includes northwest plateau region.
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South Interior (SI): All areas inland from 38° N south to the Mexican border and east to 2,000 feet elevation on the west slope of the Sierra Nevada.
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Montane (M): The Sierra Nevada from the 2,000-foot line on the west slope to the Nevada line.
Describing Nest Site Location
Use the TOPOZONE web site to provide an accurate location for the nest site you observe. Follow directions at the site to enter a "place name" for your site and then click anywhere on the interactive map. Go to the bottom of the map and click on the circle for coordinates in decimal degrees (DD.DDD). Now click on the exact spot where the eyrie is located or click on the map to move it around until you find the exact spot where the eyrie is located. Print the map and send it to us with the observation form found at this web site. Please complete an observation form for each visit.
Observing Breeding Behavior
IMPORTANT: If at any time, the falcons begin “cacking” loudly, the observer is too close to the nest and should retreat immediately! Disturbances at the nest site that cause extended periods of cacking vocalizations can lead to nest failure. Peregrines especially dislike trespassers above the nest cliff.
This survey seeks to measure three parameters of breeding behavior:
Occupied Territory - a territory where either two adults are present, or there is evidence of reproduction (e.g., one adult is observed sitting low in the nest, or eggs or young are seen). Occupancy must be established for at least one of the two (or more) 4-hour site visits.
Nest Success - a nest in which at least one young, at least 10 days old is observed or known to exist.
Productive (optional) - the number of young raised to 34 days or older.
Some behaviors can be misinterpreted as "nest-failure". To be sure that nesting activity has ceased at a site, it is important to observe the site carefully for a minimum of four hours. Many pairs begin the nesting cycle anew after nesting failure at the egg stage, usually in another eyrie.
Determining Occupancy, Success, & Productivity
It is difficult to improve on Janet Linthicum's "Observing Breeding Behavior" (Cade, et. al. 1996) for determining territory occupancy, nest success, and productivity, so we include it here in full. But since most surveyors will not be able to observe young at close hand, we offer the following method of determining the presence of young 10 days of age or more to ascertain “nesting success”.
By observing young: Between the ages of 10 and 14 days of age, young peregrines acquire a "second down" making it possible for them to maintain body heat without constant brooding by an adult. These extended absences from the nest by adults are sometimes interpreted as nest failures. Watching carefully from a distance for prey delivery is the best way to determine the presence of young more than 10 days of age. At eyries where young are visible, they begin to appear quite alert and sit upright to preen or when disturbed by the time they reach fifteen days of age.
By observing adults: In many cases it is impossible to look directly into the eyrie and observe adults and young in the nest so we have to rely on our observations of adult behavior in the vicinity of the nest to determine the presence of eggs or young. BY NO MEANS should an observer attempt to see into a nest if it might cause disturbance to the adults. An adult is almost always in the nest if the incubation of eggs is occurring so the observer must focus attention upon the eyrie. When a food exchange occurs, the male delivers food to the female in the air or at a perch and immediately goes to the nest ledge to cover the eggs while she eats. If young are present, the female may briefly pluck the food item before taking it to the nest.
Download the verbatim PDF text of "Observing Breeding Behavior" contained in, Guide to Management of Peregrine Falcons at the Eyrie, by Cade, Enderson, and Linthicum, and published by The Peregrine Fund. We thank the authors and The Peregrine Fund for permission to reprint these guidelines here.
