Piping Plovers and Least Terns of
the Great Plains and Nearby
A draft protocol for assessing piping plover reproductive success
on Great Plains alkali lakes
Protocol outline
Review plover breeding behavior, habitat, and biology (Cairns 1982, Prindiville
Gaines and Ryan 1988, Haig1992); previous plover use of local breeding sites
(e.g., map records); permit stipulations; pertinent sections of this document.
Census/survey breeding pairs on alkali lakes during 11-20 May and 1-10 June
(use the latter if only one census is to be conducted; it may be necessary
to start 3-6 days early on the largest lakes. Record distribution of pairs,
single territorial adults, and other plovers on a site map (see Methodology;
Section A; Appendix B).
Try to locate nests and count eggs during censuses of breeding pairs. In
areas of concentrated breeding (>5 pairs/km²), it may be more practical
to locate nests just after censuses. Use a technique or combination of techniques
appropriate for the situation (see Section B). Do
not approach within 3 m (10 ft); avoid leaving footprints on soft substrates
and other possible cues to predators. Mark >9 m (30 ft) away with small
rock cairns, small sticks, tongue depressors, or natural features (see Section
C). Record nest locations on breeding site maps and, ideally, include
UTM (Universal Transverse Mercator) or "Lat-Long" location by GPS (Global
Positioning System) receiver.
Monitor breeding pairs at least once, preferably twice, weekly through incubation
and fledging or until breeding failure is confirmed. After finding and marking
nests, avoid disturbing plovers on subsequent visits by observing from remote
points wherever possible. If failure is suspected, check nest site closely
after trying to locate adults and noting their behavior (see Section
E).
A nest is considered successful (i.e., ≥1 egg hatched) if chicks are
observed or if indicated by eggshell fragments plus adult behavior (see Section
E). It is unsuccessful if all eggs are missing >5 days before the expected
hatching date, if no chicks are observed and there is evidence of predation
(e.g., tracks, scat, or depredated eggs) at the nest site, or if eggs either
are abandoned or sterile. If a nest cannot be assigned to either category,
its fate should be classified as unknown.
Allow a minimum of 1 hr under good observation conditions (cool [<25
C/<75 F], calm to light wind [<30 kmph/<20 mph], no precipitation)
to account for all of a breeding pair's chicks or fledglings that should be
present. If none is observed, conduct ≥1 additional observation visit on
the earliest possible date for confirmation. Consider that young plovers may
travel ≥100-400 m (≥0.25 mi) from nests depending on their age, distribution
of other plover territories, and physical barriers. Search for and observe
adults for cues on location or fate of chicks (see Section
F). Check broods when young are 18-20 days old to estimate numbers of
fledglings. Try to monitor young plovers through 25 days of age.
Standards for determining nesting chronology and exposure-days are (these
can vary; see Section D, especially regarding fledging
age criterion):
laying period 7 d
incubation period 28 d
nesting period total 35 d
age for estimating fledging rate 18-20 d
Maintain a chronological database of observations for each breeding pair
(Appendix B).
Include all breeding pairs within the selected sample or specified population
as the basis for fledging rate calculation. Consider potential biases when
reporting nest success (see Section I).