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CEQR TECHNICAL MANUAL 1 MARCH 2014 EDITION

Below are some animal sampling techniques for invertebrates, fish, and wildlife:

INVERTEBRATES

Invertebrate surveys are generally performed for threatened and endangered species (TES), species of

special concern, or commercially important species (e.g., blue crab). Some species of butterflies,

moths, mayflies, dragonflies, beetles, and mollusks are listed by NYSDEC as either threatened or en-

dangered or as species of special concern. In addition, aquatic invertebrates, especially emergent

aquatic insect larvae and crayfish, can serve as indicators of stream health.

A variety of techniques are used for sampling invertebrates. Some of the more common methods that

may be applicable for CEQR studies are described here.

• OBSERVATION. This is often the easiest and least disruptive method to survey for inverte-

brates; however, an experienced invertebrate zoologist is required to identify specimens

observed in the field. If specific TES and special concern species are targeted, experienced

field biologists can review descriptions and life histories, examine known museum speci-

mens including similar species that could also occur in the area, and other available infor-

mation to make themselves capable of finding and identifying target species. The American

Museum of Natural History and NYCDPR’s Natural Resources Group are good sources for

specimens. Observations can be categorized as direct or indirect, both of which are de-

scribed below:

o Direct observation. Direct observations may include observing invertebrates with the

naked eye, hand magnifier or via another apparatus. It may be used for any type of in-

vertebrate species. For aquatic organisms, a mask and snorkel may be appropriate. Di-

rect observations may be made with or without collection of the organism in question.

o Indirect observation. Indirect observations may include evidence of invertebrates,

such as cast exoskeletons (exuviae), spent shells, or egg and larval stages. Spent shells

can be found at muskrat middens and along watercourses and they serve as an espe-

cially good indicator for the presence of freshwater mussels.

• INSECT NETTING. Insect netting, or sweep netting, during appropriate season and time of day

is a general method for collecting insects and consists of using a net specially tailored for

capturing flying insects.

• TRAPPING. Two types of traps used to capture invertebrates are described below:

o Light traps. Light traps use an ultraviolet or black light to attract insects, especially

moths, where they are collected in a trap or attracted to a white sheet and selectively

identified and removed. This is one of the better methods to survey moths.

o Baited traps or stations. Invertebrates are attracted to bait (e.g., honey) and become

trapped or feed at a station. Traps can be left over time but bait stations must be vis-

ited at regular intervals to increase the chance of encountering feeding individuals.

• GRAB SAMPLE. A grab sample is a single sediment sample taken from a particular location.

Various types of equipment are available for collecting grab samples. Some of the more

common sediment grab sampling devices include the Ponar sampler, the Ekman dredge,

and the Smith-McIntyre substrate sampler. Each of these provides a quantitative sample.

For a qualitative grab sample, a simple trowel or shovel can be used in shallow water.

• SURBER SAMPLER. A Surber sampler is used for quantitative sampling in shallow (30 cm or

less), flowing water. It consists of a double-framed structure, hinged along one edge, with a

ANIMAL SAMPLING TECHNIQUES

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net attached to one of the frames. One of the frames is positioned securely on the stream

bottom in riffle/run areas, and the other frame with the net is placed perpendicular to the

bottom. The operator disturbs the area encompassed by the frame placed on the bottom

and removes any attached organisms. Detached and disturbed benthic organisms then flow

with the current into the net attached to the other frame.

• DRIFT NET. This sampling device consists of a net that is anchored in flowing water to catch

macroinvertebrates that have migrated or become dislodged into the current. Sampling

should be done for a predetermined amount of time, and nets should be checked frequent-

ly to prevent clogging. Sampling between dusk and 1:00 AM is optimal.

• TOW NET. Tow nets are used for qualitative sampling of benthic invertebrates, and they in-

clude devices ranging from simple sled-mounted nets to complex devices. These nets are

towed behind boats and can yield quantitative results when towed for a standardized unit

of time.

• KICK OR DIP NET. These types of nets are very versatile for collecting in shallow, flowing water.

Generally, these devices are used for qualitative sampling, although when used with a

standardized kicking technique, they can also be used for semi-quantitative sampling.

• CLAM RAKE. This device selectively retains larger items and organisms and is appropriate for

use when performing qualitative sampling for mollusks. Generally, it is used along shore-

lines of creeks and rivers to supplement information obtained from other sampling tech-

niques.

• TRAWL. A trawl is a funnel type net towed behind a boat. Generally, the only invertebrate

targeted using this method is the blue crab, in which case the net would be set along the

bottom of the water body.

• ARTIFICIAL SUBSTRATE SAMPLER. These types of samplers are of a standard composition and

configuration and are placed in the water for a predetermined period of time, after which

the degree of colonization by macroinvertebrates is determined. A variety of artificial sub-

strate samplers are available, including the Hester-Dendy sampler and the basket sampler.

FISH

Fish survey techniques are specific to species and habitat types. Generally, more than one technique

should be used, since most methods target only certain populations.

• OBSERVATION. Direct observations of fish species can be made from shore or from a boat.

Sunglasses with polarizing lenses or binoculars are often useful tools when using this tech-

nique. Although observations are useful, they seldom account for all species present. Thus,

if used, they should be combined with some of the additional techniques described below.

• ELECTROSHOCKING. Electroshocking is probably the best method to use for general fish sur-

veys when there is no specific target species. Nevertheless, its effectiveness varies accord-

ing to the species, habitat, and the size of the fish. Although the operative salinity range of

the shocking units varies, electroshocking is not effective in moderate to high conductivity

water bodies. Three types of electroshocking units are available.

o Backpack Electroshocker. For a backpack electroshocker, the power unit is strapped

backpack-style to the operator’s back, and the anode and cathode probes are held by

hand usually in front of the operator, although the cathode probe may trail behind.

Since this type of electroshocker is operated while wading in the waterbody, it can on-

ly be used in smaller streams, creeks, and brooks.

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o Stream Electroshocker. A stream electroshocker consists of a power unit, usually

water on a small boat. The operator operates the probes while wading in the water-

body, and usually two additional people are required to net the fish. This type of elec-

troshocker is generally reserved for creeks, brooks, and small rivers.

o Boat Electroshocker. A boat electroshocker is generally used in deeper water (rivers,

large ponds, and lakes). For this type of electroshocker, the entire unit, including the

power source, generator and probes, is housed on a boat. Generally, one person

guides the boat while two people net the fish and operate the probes. The probes are

usually operated by pressing a pedal.

• TRAWLS. A trawl is a funnel-type net towed behind a boat. It can be set at different depths in

the water column and is generally used for juvenile and adult fish.

• SEINES. A seine is a type of net that is used along the shoreline to encircle fish and pull them

to shore. Seines work well in little to moderate current where there are few underwater

obstructions and the shoreline is generally sloping. This method is used to collect fish that

utilize nearshore habitat.

• TRAP NETS. Trap nets are designed to lead migrating fish into the trap of a net. Various de-

signs of trap nets exist, but they typically have one to three leads or wings of webbing that

are designed to intercept migrating fish. The leads and wings extend from the mouth of the

net to an anchor. When fish encounter these obstacles, they swim around them and into

the mouth of the net. Use of trap nets is a passive method that works well in waters with

little current. This method causes little damage to the fish, except that predation can occur

in the trap. It is also selective for migratory fish species that swim parallel to shorelines or

structures. Trap nets are most commonly used in nearshore or shallow water.

• GILL NETS. Although the use of this method is strongly discouraged within the City, gill nets

are nets with a specially designed mesh size that cause fish to become entangled in the net

by their gills. The target fish are too large to move through the net, and attempt to escape

by swimming backwards causes the gills to catch in the net. Gill nets are generally used in

non-flowing waters, but they are sometimes also used in larger rivers. Since gill nets may

cause severe damage to fish (loss of slime coat, loss of scales, stress, and possible suffoca-

tion), they are not commonly used.

• LARVAL/ICHTHYOPLANKTON NETS. Larval or ichthyoplankton nets are fine mesh nets that capture

early life stages of fish. They can be towed behind boats along the bottom or in the water

column. Some are attached to benthic sleds. Their placement depends on the type of eggs

(demersal, adhesive, and pelagic) and the behavior of larvae (pelagic, demersal, etc.). Use

of these nets should be timed according to the occurrence period of the species and life

stage(s) targeted.

• BENTHIC SLED. A benthic sled is a sled-like structure that is towed behind a boat and has a net

attached to it. Most often, this sampling device is used in conjunction with a larval net to

collect early life stages of fish that occur along the bottom.

• CREEL SURVEY. A creel survey is selective for game species and consists of surveying anglers

about their catch. In some cases, the captured fish can be weighed and identified. In other

cases, information is obtained verbally from the angler.

• HOOK & LINE. This method employs the use of a rod and reels and can be employed from a

boat, shoreline, pier, or dock. Since this is a selective, often time-consuming method, it

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CEQR TECHNICAL MANUAL 4 MARCH 2014 EDITION

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should generally only be used for qualitative studies of species presence/absence and to

supplement other techniques.

• DIPNET. A dipnet is a small hand-held net that can be used to collect small fish along shore-

lines, banks, etc. Like the hook & line method, it is selective for certain species and is often

time-consuming. It should therefore only be used in conjunction with other techniques.

WILDLIFE

The design of wildlife studies requires knowledge of the species expected to be present, especially

when threatened and endangered species or species of special concern are likely to occur. Thus, in-

formation on habitat types, as well as general information on the seasonal occurrence, activity pat-

terns, and behavior of the wildlife expected in the area, is essential in order to select stations and to

time the surveys to maximize the chances of encountering various species. In addition, reconnaissance

surveys help to identify what species may be present in the area and to select sampling locations. Are-

as of potentially suitable habitat for Threatened or Endangered Species (TES) or species of special con-

cern should be searched at times when such species are most likely to be found. Other special habitats

should also be selected and searched. These might include vernal pools, seeps, streams, rock out-

crops, snags, etc. For species-specific TES surveys, a trained wildlife biologist with extensive experi-

ence finding the target TES should be used. Performing wildlife observations requires trained person-

nel with the ability to identify rapidly wildlife species by sight, sound, and sign. Figures, photos, or

even video may aid in illustrating the location and distribution of sampling stations for the various

types of surveys used.

• OBSERVATION. Observations of wildlife can either result from targeting certain species at cer-

tain times of day or night and during certain seasons, or they can be incidental while con-

ducting other surveys. For example, incidental observations of wildlife can be recorded

while performing wetlands delineation. Incidental observations are not adequate for analy-

sis of potential impacts to wildlife and should only be used when only a general idea of the

types of wildlife utilizing a site is necessary or to focus additional wildlife surveys. Both fo-

cused and incidental observations can be direct or indirect, as follows:

o Direct observation. Direct observations may include observing wildlife with the naked

eye, through binoculars, spotting scopes, or via another apparatus. This technique can

be used for any type of wildlife species. Direct observations can be made with or

without collection of the organism. The probability of direct observation of small

mammals, reptiles, and amphibians is increased by searching under debris, logs, and

rocks.

o Indirect observation. Indirect observations include evidence of wildlife, such as am-

phibian and bird calls, bird songs, tracks, droppings, burrows, runs, caches, and re-

mains, such as feathers, bones, skeletons, and roadkill.

Field surveys should be designed to follow standardized methods, such as those described

in technical publications and in the current scientific literature.

• LIVE & SNAP TRAPS. Because small mammals are secretive and nocturnal, trapping may be the

best way to determine if they are present. Small mammals may be captured using live traps

(traps designed not to kill the animal) and snap traps (traps designed to kill the animal in-

stantaneously). Live traps work well for a variety of small mammals, and if needed, various

baits can be used to target certain species. Snap traps should be avoided unless required by

a natural resource agency. If used, specimens killed should be salvaged and provided to

museums with information on where and when they were collected. Trapping results can

provide information on both absolute (if live traps are combined with marking) and relative

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CEQR TECHNICAL MANUAL 5 MARCH 2014 EDITION

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abundance. Care should be taken to make any traps set out as inconspicuous as possible

due to the sometimes-heavy traffic that can occur in some natural areas. Traps may need

to be checked more often due to possible human interference. City, state and possibly fed-

eral scientific collection permits would be required to use this sampling method depending

on the property where the research is conducted, and a NYSDEC License to Collect or Pos-

sess would likely be required for trapping activity. Consultation with relevant agencies is

necessary to determine any permitting requirements.

• PITFALL TRAPS. Pitfall traps are depressions in the ground that animals fall into and from

which they cannot escape. They work best when used together with drift fences, which are

short vertical fences radiating out from the trap that act as runways that draw the ani-

mal(s) into the trap. These types of traps work well for shrews, other small mammals, and

salamanders. The trap should be deep enough to prevent escape, but not so deep that it

causes injury to the animal. If salamanders are targeted or are likely to be captured,

enough water should be placed in the trap to prevent desiccation, but not too much to

cause drowning of the animal(s). Pitfall traps should be designed with raised covers to pre-

vent drowning due to excessive water accumulation in the trap and to prevent excessive

sun exposure. The use of pitfall traps should be carefully considered prior to use, as they

must be checked at frequent intervals to prevent undue heat or cold exposure, stress, or

starvation of the trapped animal(s). This is a time-intensive method. City, state and possibly

federal scientific collection permits would be required to use this sampling method de-

pending on the property where the research is conducted, and a NYSDEC License to Collect

or Possess would likely be required for trapping activity. Consultation with relevant agen-

cies is necessary to determine any permitting requirements.

• COVER BOARDS. Cover boards are placed on the ground to attract small mammals, snakes,

and salamanders for long term studies. They are left out for extended periods of time and

are checked occasionally. The species found under the boards are identified and recorded.

Cover boards can be made of a variety of materials, such as exterior plywood or corrugated

roofing. City, state and possibly federal scientific collection permits would be required to

use this sampling method depending on the property where the research is conducted, and

a NYSDEC License to Collect or Possess would likely be required for trapping activity. Con-

sultation with relevant agencies is necessary to determine any permitting requirements.

• HAIR SNARES. Hair snares are devices made of carpet attached to a small (about 4x4 inches)

piece of wood that is nailed to a tree approximately two feet above the ground. The device

may be modified by attaching a piece of Velcro. The hair snare is then “baited” with com-

mercially available animal scent that lures the target animal to the snare. The scent induces

rubbing on the snare, and hairs of the animal are left on the device for later identification.

This method is appropriate for identifying the presence of large carnivores, such as coyote

and fox, and it requires a knowledgeable biologist with the ability to identify large carni-

vore hairs.

• HAIR SNARE OR TRACK TUBES. Hair snare tubes are tubes with Velcro inserts used to snare the

fur of small mammals passing through them for identification and analysis. Track tubes are

covered with a surface that will leave impressions of animal tracks. These tubes can be

baited, usually with food, which induces the animal to enter the tube. Similar to a regular

hair snare, the use of hair snare tubes requires a knowledgeable biologist with the ability to

identify small mammal hairs. City, state and possibly federal scientific collection permits

would be required to use this sampling method depending on the property where the re-

search is conducted, and a NYSDEC License to Collect or Possess would likely be required

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CEQR TECHNICAL MANUAL 6 MARCH 2014 EDITION

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for trapping activity. Consultation with relevant agencies is necessary to determine any

permitting requirements.

• OWL PELLETS. Owls are known to roost in certain areas. If owls are foraging on the site and

their roosts are known, their pellets can provide a source of local small mammal’s skulls

and bones that can be sorted and identified. This technique requires knowledge of the for-

aging range of the species of owl in question in order to determine whether the prey could

have been captured off-site.

• CALL PLAYBACK. Call playback is usually used to survey for birds, but it can also be used for

coyotes. This method entails playing recordings of calls or songs and listening for a re-

sponse. The call or song can be of the species being surveyed or of another species that is

expected to elicit a call from the species being surveyed. Calls are generally played for

three minutes followed by a one-minute listening period. Examples of uses of the call play-

back technique include, but are not limited to, the following:

• DIURNAL RAPTOR SURVEYS. Recordings of selected hawks and owls can be played at call stations

to stimulate diurnal raptors to respond. Call stations for hawks (Cooper's, red-shouldered,

northern goshawk, and sharp-shinned) are surveyed from sunrise to about midmorning.

Calls used at hawk stations should include the great horned owl because hawks often re-

spond to this call. The barred owl call can also be played in the early morning, as this spe-

cies often responds during these hours.

• NOCTURNAL RAPTOR (OWL) SURVEYS. Recordings of owl calls can be played to stimulate owls to

respond. Call stations for owls are surveyed from sunset to early morning using specific

calls for the species being surveyed.

• MARSH BIRD SURVEYS. Marsh birds are surveyed during the evening and at night. During these

surveys, playback recordings of American bittern, least bittern, black rail, sora rail, Virginia

rail, pied-billed grebe, sedge wren, clapper rail, and marsh wren should be played, either

from a canoe or on foot.

• TURTLE TRAPS. Turtle traps are traps with funnel-shaped entrances that minimize the ability

of the animal to exit the trap. It can have wings or leads to draw the animal into the trap.

Turtles traps set in water should be staked so that part of the trap is above water to pre-

vent drowning of the animal. Like other live trapping devices, these traps must be moni-

tored at frequent intervals to prevent undue stress or starvation of the trapped animal.

City, state and possibly federal scientific collection permits would be required to use this

sampling method depending on the property where the research is conducted, and a

NYSDEC License to Collect or Possess would likely be required for trapping activity. Consul-

tation with relevant agencies is necessary to determine any permitting requirements.

ADVANCED TECHNIQUES

Advanced survey techniques for fish and wildlife studies are generally not required for CEQR evalua-

tions. However, under unique circumstances, they may be the best way to determine the presence,

movements, and habitat use of a particular species if such information is necessary. Examples of some

advanced techniques include radiotelemetry, banding, marking, bat surveys, mist netting, and nest

surveys/counts. These methods would generally not be allowed for federally threatened or endan-

gered species.

• RADIOTELEMETRY. Radiotelemetry involves attaching a radiotransmitter to an organism and

using a receiver to detect radiofrequencies emitted by the transmitter. This technique is an

efficient method to locate an individual, track its movements, and determine its habitat us-

age and home range. Radiotelemetry can be used to determine if a TES or species of special

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CEQR TECHNICAL MANUAL 7 MARCH 2014 EDITION

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concern identified outside the project area moves into the project area, thereby subjecting

it to project-related effects. This technique is also especially useful for determining corri-

dors used by individuals to move to or from a project area or specific habitat (such as a

nesting site, overwintering site, foraging area, etc.). However, this technique is very expen-

sive and thus is rarely applicable for CEQR evaluations. City, state and possibly federal sci-

entific collection permits would be required to use this sampling method depending on the

property where the research is conducted, and a NYSDEC License to Collect or Possess

would likely be required for trapping activity. Depending on the species of interest, federal

auxiliary marking permits may be required. Consultation with relevant agencies is neces-

sary to determine any permitting requirements.

• BANDING. Banding can be used for birds or bats and consists of attaching a circular band

with a unique identification code to the leg (or neck for long-necked birds) of the captured

organism. When the organism is recaptured, it can be identified to the individual. Banding

procedures are generally used to determine long distance movements and usually have lit-

tle practical use for CEQR evaluations. However, in unique circumstances, banding may be

used to determine local movements and population estimates. This technique is time con-

suming, and its usefulness should be considered carefully prior to implementing it. City,

state and possibly federal scientific collection permits would be required to use this sam-

pling method depending on the property where the research is conducted, and a NYSDEC

License to Collect or Possess would be required for trapping activity, as would a federal bird

banding permit from the USGS-Bird Banding Laboratory. Consultation with relevant agen-

cies is necessary to determine any permitting requirements.

• MARKING. Marking encompasses any method to attach a unique identification number or

other code to individual fish, amphibians, reptiles, and mammals. Marking for these organ-

isms can take the form of tagging, shell notching, painting, toe clipping, branding, body

markings, and other methods. Marking studies are generally used to determine local

movements, estimate local population size/density, and to avoid counting the same indi-

vidual more than once. City, state and possibly federal scientific collection permits would

be required to use this sampling method depending on the property where the research is

conducted, and a NYSDEC License to Collect or Possess would likely be required for trap-

ping activity. Depending on the species of interest, federal wildlife marking permits may be

required. Consultation with relevant agencies is necessary to determine any permitting re-

quirements.

• BAT SURVEYS. Surveys for bats are difficult and time consuming and should not be necessary

for CEQR evaluations except under very exceptional circumstances. To survey for bats, bat

detectors, mist netting, radiotelemetry, and searching underground areas, tunnels, mines,

old barns, and attics, and other habitat are used. City, state and possibly federal scientific

collection permits would be required to use this sampling method depending on the prop-

erty where the research is conducted and the method used, and a NYSDEC License to Col-

lect or Possess would be required for trapping activity. Depending on the species of inter-

est, federal auxiliary marking permits may be required. Consultation with relevant agencies

is necessary to determine any permitting requirements.

• MIST NETTING. Mist nets are nets used to capture birds and bats. They are made of a fine

threaded material that is difficult to see and are placed in areas through which birds and

bats are known to travel. Birds and bats are captured in the net and removed by field per-

sonnel for identification and/or banding. Mist netting can cause significant stress to an an-

imal, especially if the animal is left in the net for long durations. Thus, it is necessary to

monitor the net at frequent intervals, making this method very time consuming. In addi-

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tion, significant training and experience are required. Although this method is sometimes

useful for breeding bird surveys and movement studies, this method would not normally be

used for CEQR evaluations and should be avoided unless specifically required. City, state

and possibly federal scientific collection permits would be required to use this sampling

method depending on the property where the research is conducted, and a NYSDEC Li-

cense to Collect or Possess would be required for trapping activity, and additional federal

permits may also apply. Consultation with relevant agencies is necessary to determine any

permitting requirements.

• NEST SURVEYS/COUNTS. Nest surveys or counts entail physically counting and/or monitoring

bird nests to obtain information on productivity and territoriality. These types of surveys

are often labor-intensive and time consuming and require significant training in identifying

nests. In addition, nests are usually very difficult to identify correctly. Therefore, this tech-

nique should only be used when necessary and only for those species whose nests are easi-

ly identified.

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