rabbits

Rabbit Population Densities at the Sevilleta National Wildlife Refuge, New Mexico (1992-2004)

Abstract: 

This study measured the population dynamics of black-tail jackrabbits (Lepus californicus) and desert cottontail rabbits (Sylvilagus auduboni) in the grasslands and creosote shrublands of McKenzie Flats, Sevilleta National Wildlife Refuge.  The study was begun in January, 1992, and continued quarterly each year.  Rabbits were sampled via night-time spotlight transect sampling along the roads of McKenzie Flats during winter, spring, summer, and fall of each year.  The entire road transect was 21.5 miles in length. Measurements of perpendicular distance of each rabbit from the center of the road were used to estimate densities (number of rabbits per square kilometer) via Program DISTANCE.  Results from 1992 to 2002 indicated that spring was the peak density period of the year, with generally steady declines through the year until the following spring. Evidence of a long-term "cycle" (e.g., the 11 year cycle reported for rabbits in the Great Basin Desert) did not appear in the Sevilleta rabbit populations.

Core Areas: 

Data set ID: 

113

Additional Project roles: 

304
305

Keywords: 

Purpose: 

The purpose of the study was to assess the dynamics of rabbit populations in the grasslands and creosote shrublands of the Sevilleta NWR.  Rabbits are important herbivores in these habitats, and can influence NPP and plant species composition.  In turn, these animals also provide high-quality prey for many of the Sevilleta's mammal and reptile carnivores and birds of prey.  Density data on rabbits can be used to calculate herbivore pressure on the plant communities.

Data sources: 

sev113_rabbitdens_20040226.txt

Methods: 

When the samples were collected: The samples were collected in winter, spring, summer, and fall, of each year.  Rabbit populations were sampled during a single night during each of these four seasons per year.  Dates of collection varied in some years, but generally the sampling was conducted in January, April, July, and October.

Sampling Design: The rabbits were sampled along 21.5 miles of roadway that was broken up into four "legs" of varying lengths.

Leg A:  Black Butte southward to Five Points (5.7 miles).

Leg B:  Five Points eastward to the turnoff before Palo Duro Canyon (4.1 miles).

Leg C:  Palo Duro turnoff northward to the old McKenzie Headquarters site (6.1 miles).

Leg D:  McKenzie Headquarters site northwestward to Black Butte (5.6 miles).

Measurement Techniques: The rabbit surveys were conducted at night using spotlights. Surveys began one hour after sunset, when no trace of sunlight or dusk remained.  Beginning in 1998, samples were taken only during full-moon periods. A pickup truck was driven slowly (8-10 miles per hour) along the road of the 21.5 mile circuit.  Two (or more) observers stood in the bed of the pickup truck, and scanned the left and right sides (respectively) of the road with spotlights, while the driver kept watch for rabbits directly in front in the road.  During 1992, the spotlights were Q-Beam 500,000 candlepower spotting lights, with both flood and spot settings (spot settings were used during the rabbit sampling).  From 1993 through 1996, Q-Beam spotlights with 1,000,000 candlepower were used.  In 1997, new spotlights with 3,000,000 candlepower were used; these lights were set permanently on "flood", but illuminated well at distances previously reached by the spot settings of the less-powerful spotlights.  

In addition to the spotlights used by the standing observers in the bed of the pickup truck, two spotlights mounted on the pillar posts of the truck's cab were turned on and set for the roadsides ahead of the truck; these lights, coupled with the high-beam setting of the truck's headlights, illuminated the road in front of the truck for approximately 100 meters. When a rabbit was observed, one person's spotlight illuminated the spot at which the rabbit was first seen.  The second person's spotlight would track the rabbit, so that it was not counted twice.  A meter tape was walked out from the center of the truck bed (which equalled the center of the road) in a perpendicular direction from the road to the location at which the rabbit was first observed.  That distance was measured and recorded to the nearest meter.

If a rabbit was observed in the middle of the road, the distance was recorded as zero.  Beginning in January, 2000, perpendicular distances to the rabbits were taken with a laser range finder, with accuracies of less than 1 meter (accuracies were tested before field use and confirmed to be <1m).  Generally, rabbits within 100 meters of the road could be seen relatively clearly with all three types of spotlights. Other data recorded included (1) the odometer reading in miles from the beginning of the sample at Black Butte (odometers were reset to zero at the start of the sample), (2) whether the rabbit was on the Left or Right side of the road, and (3) the species of rabbit.  In addition, incidental data were recorded on weather conditions, presence of clouds and moon, and the time at which the survey was begun, along with the times at which each Leg was begun and finished.  Finally, the names of the people on the sampling crew were recorded.

Analytical Procedures: The perpendicular distance data were entered into Program DISTANCE to estimate the total density of rabbits in the study area. Values were computed as numbers of individuals per square kilometer In the analyses, if there were sufficient numbers of rabbits (>10 per leg), the difference legs were analyzed separately, and the resulting mean densities were estimated by averaging the four leg estimates.  In the results tables below, these instances are indicated by the category, "MEAN".  If sample sizes were too small to estimate the four legs separately, then all the rabbit observations were pooled together, and a density estimate for the entire 21.5 mile survey was calculated. These results are indicated by the category, "ALL".

Quality Assurance: 

The program DISTANCE command codes were as follows:

Options;

Title='SEVILLETA RABBIT

DENSITIES';

Type=Line;


Length/Units='Miles';

Area/Units='Hectares';

Distance=Perp/Measure='Meters'/Exact;

Object=Single;

End;


Data;

Stratum/label='DATE ENTERED HERE';

Sample=1/Label='ALL

LEGS, DATE ENTERED HERE'/Effort=21.5;

DISTANCE DATA ENTERED HERE, SEPARATED BY COMMAS;

End;


Estimate;

Est /key=uniform /adj=cosine  /select=sequential /criterion=AIC /monotone=weak;

Est /key=uniform /adj=hermite /select=sequential /criterion=AIC /monotone=weak;

Est /key=hnormal /adj=cosine  /select=sequential /criterion=AIC /monotone=weak;

Est /key=hnormal /adj=hermite /select=sequential /criterion=AIC /monotone=weak;

Pick=AIC;

Density by sample;


End;

Small Mammal Exclosure Study (SMES) Rabbit Feces Data from Chihuahuan Desert Grassland and Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (1995-2005)

Abstract: 

The purpose of this study is to determine whether or not the activities of small mammals regulate plant community structure, plant species diversity, and spatial vegetation patterns in Chihuahuan Desert shrublands and grasslands. What role if any do indigenous small mammal consumers have in maintaining desertified landscapes in the Chihuahuan Desert? Additionally, how do the effects of small mammals interact with changing climate to affect vegetation patterns over time?

This is data for numbers rabbit fecal pellets counted on each of the Small Mammal Exclosure Study (SMES) plots. Rabbit fecal pellets were counted from each of the 36 one-meter2 quadrats twice each year when vegetation was measured.

Data set ID: 

91

Core Areas: 

Keywords: 

Purpose: 

The purpose of this study is to determine whether or not the activities of small mammals regulate plant community structure, plant species diversity, and spatial vegetation patterns in Chihuahuan Desert shrublands and grasslands. What role if any do indigenous small mammal consumers have in maintaining desertified landscapes in the Chihuahuan Desert? Additionally, how do the effects of small mammals interact with changing climate to affect vegetation patterns over time? This study will provide long-term experimental tests of the roles of consumers on ecosystem pattern and process across a latitudinal climate gradient. The following questions or hypotheses will be addressed.

1) Do small mammals influence patterns of plant species composition and diversity, vegetation structure, and spatial patterns of vegetation canopy cover and biomass in Chihuahuan Desert shrublands and grasslands? Are small mammals keystone species that determine plant species composition and physiognomy of Chihuahuan Desert communities? Do small mammals have a significant role in maintaining the existence of shrub islands and spatial heterogeneity of creosotebush shrub communities?  

2) Do small mammals affect the taxonomic composition and spatial pattern of vegetation similarly or differently in grassland communities as compared to shrub communities? How do patterns compare between grassland and shrubland sites, and how do these relatively small scale patterns relate to overall landscape vegetation patterns?

3) Do small mammals interact with short-term (annual) and  long-term (decades) climate change to affect temporal changes in vegetation spatial patterns and species composition?

4) Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundance’s of other consumers such as ants and grasshoppers?

Data sources: 

sev091_smesrabbit_20160308.csv

Methods: 

Experimental Design: 

There are 2 study sites, the Five Points grassland site, and the Rio Salado creosotebush site. Each study site is 1 km by 0.5 km in area. Three rodent trapping webs and four replicate experimental blocks of plots are randomly located at each study site to measure vegetation responses to the exclusion of small mammals. Each block of plots is 96 meters on each side. Each block of plots consists of 4 experimental study plots, each occupying 1/4 of each block. The blocks of study plots are all oriented on a site in a X/Y coordinate system, with the top to the north. Treatments within each block include one unfenced control plot (Treatment: C), one plot fenced with hardware cloth and poultry wire to exclude rodents and rabbits (Treatment: R), and one plot fenced only with poultry wire to exclude rabbits (Treatment: L). The three treatments were randomly assigned to each of the four possible plots in each block independently, and their arrangements differ from block to block. Each of the three plots in a replicate block are separated by 20 meters. 

Each experimental measurement plot measures 36 meters by 36 meters. A grid of 36 sampling points are positioned at 5.8-meter intervals on a systematically located 6 by 6 point grid within each plot. A permanent one-meter by one-meter vegetation measurement quadrat is located at each of the 36 points. The 36 quadrats are numbered 1-36, starting with number 1 in the top left corner (north-west) of each plot (top being north), and running left (west) to right (east), then down (south) one row, and then right (east) to left (west), and so on Quadrat/rebar number one is in the northwest corner of each plot, and numbers 1-6 are across the north side of the plot west to east, then quadrat/rebar number 7 is just south of quadrat/rebar number 6, and rebar numbers increase 7-12 east to west, and so on. 3-inch nails were originally placed in the top left (north-west) corner of each quadrat. These may be difficult to see. A 3-meter wide buffer area is situated between the grid of 36 points and the perimeter of each plot.

While measuring vegetation on each quad, the total number of rabbit feces (pellets) that  were see on each quadrat was counted and recorded.

Maintenance: 

07/07/03  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using periods (.), duplicates of data points were removed, and errors were corrected.  If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Removed Species, Comments, and Per fields.  Tape field was changed to ID# and observations made in the Per field were moved to the new ID# field.  No observations were made in the tape field.  EC field was added and NA was recorded in this field for this year.  Date MM/DD/YY field was changed to just DATE.  Other changes in the fields include PLT to PLOT, BLK to BLOCK, and CNT to COUNT. 

- Missing all Plots for Block 1 at the Grassland site for the spring except BLOCK 1 PLOT 1 TRT L.  Other Plots that are missing are Site G Block 2 Plot 3 Treatment C, Site G Block 3 Plot 3 Treatment R, and Site G Block 4 Plot 2 Treatment C. These plots are from the spring field season.  All plots are present for the fall, but with several data points missing.

-Missing plots are Site G Block 1 Plot 2 Treatment R and Site G Block 2 Plot 1 Treatment L.  These plots are from the fall field season.  All plots are present for spring field season. 

- Any empty cells were filled in with either a period for missing data or an NA for not applicable.

- Quads 32-36 were originally classified as Trt C in the fall at the Creosote site for Blk 3 Plt 2.  Changed the Trt to Trt R.

- Quads 10-16 were originally classified as TRT C in the fall at the Grass Site for BLOCK 4 PLOT 1.  Changed the TRT to TRT R.

- For the fall field season at the Grass Site, BLOCK 2 PLOT 4 TRT R QUAD 7 was classified as Creosote, changed to Grass Site. 

- Quads 21-24 were originally classified as Trt C in the spring at the Grass site for Blk 4 Plt 3.  Changed the Trt to Trt L.

- Quads 10-17 were originally classified as TRT C in the spring at the Creosote Site for BLOCK 2 PLOT 2, changed the TRT to TRT L.

- Spring Field Season Changes

For BLOCK 1 PLOT 2 TRT R and BLOCK 2 PLOT 1 TRT L all quads classified as Creosote Site, changed to Grass Site.

For quads 1-18 at the Creosote Site for BLOCK 2 PLOT 1 TRT C, originally classified as PLOT 4, changed to PLOT 1.

For Creosote Site BLOCK 4 PLOT 2 TRT C: Quads 1-4, 28-35 originally PLOT 1 changed to PLOT 2 Quads 5-19 originally PLOT 3 changed to PLOT 2

- Fall Field Season Changes

For quads 1-18 at the Creosote Site for BLOCK 1 PLOT 4 TRT R, originally classified as PLOT 3, changed to PLOT 4.

- Spring Field Season Changes

For Grass Site BLOCK 1 PLOT 4 TRT C Quads 1-30, originally classified as BLOCK 2, changed to BLOCK 1.

For Grass Site BLOCK 3 PLOT 4 TRT C Quads 20-36, originally classified as BLOCK 4 PLOT 3, changed to BLOCK 3 PLOT 4.  

- Fall Field Season Changes

For Creosote Site BLOCK 2 PLOT 2 TRT L, date changed from 10/09/00 to 11/09/00 for quads 26-36.

For Grass Site BLOCK 1 PLOT 4 TRT C, date changed from 10/06/00 to 11/06/00 for quads 23-29.    

 - Any empty cells were filled in with either a period for missing data or an NA for not applicable.

 - Terri Koontz

07/14/03  - Modified metadata to correct format.

- Terri Koontz

07/21/03  - Spring Field Season Changes

For Grass Site BLOCK 2 PLOT 1 TRT L, there were two observations for some quads that had different dates (05/02/95, 05/03/95, and 05/04/95).  All data points with either 05/02/95 or 05/03/95 were changed to BLOCK 1 PLOT 1 TRT L.  This was done because one other plot for BLOCK 2 had some quads with this same date.  Also, it seemed logical that BLOCK 1 would have been measured first.

- Terri Koontz

07/29/03  – For fall at the Grass Site BLOCK 1 PLOT 4 TRT C QUADS 10-18 had double observations.  For one set of observations, the BLOCK was changed to BLOCK 3.  This was determined by looking at another year for vegetation data to see which set had similar values and species composition for BLOCK 3.

 - Terri Koontz

07/30/03  - Quads 11-14 were originally classified as TRT C in the spring at the Creosote Site for BLOCK 3 PLOT 4, changed TRT to TRT L.

- Terri Koontz

07/22/03  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using periods (.), duplicates of data points were removed, and errors were corrected.  If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE.

- Fall Field Season Changes

Changed dates to reflect that data was measured in 2001 and not in the 1970s.

Changed in the ID# field ‘1’ to SMESVQF01CR1, ‘2’ to SMESVQF01CR2, and ‘3’ to SMESVQF01CR3.

For Creosote BLOCK 2 PLOT 3 TRT R QUADS 34 and 36, originally BLOCK 1 PLOT 3 TRT R, changed BLOCK 1 to BLOCK 2. 

For Grass BLOCK 3 PLOT 4 TRT C, originally recorded as Creosote Site, changed to Grass Site.

For Grass BLOCK 4 PLOT 2 TRT C, originally recorded as Creosote Site, changed to Grass Site.

- Any empty cells were filled in with either a period for missing data or an NA for not applicable.

- Terri Koontz

03/14/06  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK.

- Changed dates to reflect that data was measured in 2002 and not in the 1970s.

- Changed to "1" in the EC field with comments.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

03/15/06  - For the Spring field season at the Creosote site, Plots missing are BLK 1 Plot 1 Trt C and BLK 3 Plot 3 Trt C. These plots are added to the dataset as missing values.

- Metadata was modified to correct format.

- Yang Xia

03/23/06  - changed start date from september 1995 to May 1995 in the research Hypotheses, since the data collection was starting on 05/02/95. 

- Yang Xia

05/02/06  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK.

- Changed dates to reflect that data was measured in 2003 and not in the 1970s. for the data of measured in August, changed to October. 

- Changed to "1" in the EC field with comments.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

06/12/06  - Checked data for missing data points, doubles, and errors.  Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK.

- Changed dates to reflect that data was measured in 2004 and not in the 1970s and 1990s. 

- Changed to "1" in the EC field with comments.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

06/14/06  - Modified metadata to correct format.

- For Creosote Site in the Spring, changed BLOCK 4 PLOT 1 TRT C QUAD 17-21 to BLOCK 4 PLOT 1 TRL L QUAD 17-21.

- For Grassland in the Spring, changed BLOCK 4 PLOT 1 TRT C QUAD 31-36 TO BLOCK 4 PLOT 1 TRT R QUAD 31-36.

- Yang Xia

06/26/06  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK. Tapeid was changed ID #.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

07/03/06  - Modified metadata to correct format. 

- An NA for not applicable in the EC field for 2005.

- Yang Xia

Additional information: 

Additional Information on the personnel associated with the Data Collection / Data Processing

Sevilleta Field Crew Employee History

Megan McClung, April 2013-present, Stephanie Baker, October 2010-Present, John Mulhouse, August 2009-Present, Amaris Swann, August 25, 2008-January 2013, Maya Kapoor, August 9, 2003-January 21, 2005 and April 2010-March 2011, Terri Koontz, February 2000-August 2003 and August 2006-August 2010, Yang Xia, January 31, 2005-April 2009, Karen Wetherill, February 7, 2000-August 2009, Michell Thomey, September 3, 2005-August 2008, Jay McLeod, January 2006-August 2006, Charity Hall, January 31, 2005-January 3, 2006, Tessa Edelen, August 15, 2004-August 15, 2005, Seth Munson, September 9, 2002-June 2004, Caleb Hickman, September 9, 2002-November 15, 2004, Heather Simpson, August 2000-August 2002, Chris Roberts, September 2001-August 2002, Mike Friggens, 1999-September 2001, Shana Penington, February 2000-August 2000.

Rabbit Population Dynamics in Chihuahuan Desert Grasslands and Shrublands at the Sevilleta National Wildlife Refuge, New Mexico (1992-present)

Abstract: 

This study explores the population dynamics of black-tail jackrabbits (Lepus californicus) and desert cottontail rabbits (Sylvilagus auduboni) in the grasslands and creosote shrublands of McKenzie Flats, Sevilleta National Wildlife Refuge. The study was initiated in January 1992, and continues quarterly each year. Rabbits are sampled via night-time spotlight transect sampling along the roads of McKenzie Flats once during winter, spring, summer, and fall. The route is 21.5 miles long. Measurements of perpendicular distance of each rabbit from the center of the road are used to estimate densities (number of rabbits per square kilometer) via Program DISTANCE. Results from January 1992 to May 2004 indicated that spring was the period of peak density period, with generally steady declines through the rest of the year until the following spring. Evidence of a long-term "cycle" (e.g., the 11-year-cycle reported for rabbits in the Great Basin Desert) does not appear in the Sevilleta rabbit populations.

Core Areas: 

Data set ID: 

23

Additional Project roles: 

280
281
282
283
284

Keywords: 

Purpose: 

The purpose of the study is to assess the dynamics of rabbit populations in the grasslands and creosote shrublands of the Sevilleta NWR. Rabbits are important herbivores in these habitats, and can influence net primary productivity and plant species composition. In turn, these animals also provide high-quality prey for many of the Sevilleta NWR's carnivores and birds of prey. Density data on rabbits can also be used to calculate herbivore pressure on the plant communities.

Data sources: 

sev023_rabbitpopns_20150310.txt

Methods: 

Sampling Design:

The rabbits are sampled along 21.5 miles of roadway that is broken up into four "legs" of varying lengths.

Leg A:Black Butte southward to Five Points (5.7 miles).

Leg B:Five Points eastward to the turnoff before Palo Duro Canyon (4.1 miles).

Leg C: Palo Duro turnoff northward to the old McKenzie Headquarters site (6.1 miles).

Leg D: McKenzie Headquarters site northwestward to Black Butte (5.6 miles).

Sample Unit:

Individual rabbit.

Frequency of Sampling:

Sampled one night per season, four seasons per year.

Technique Citations:

Buckland, S. T., D. R. Anderson, K. P. Burnham, and J. L. Laake.1993. Distance Sampling. Estimating abundance of biological populations. Chapman and Hall, New York.  446 pp.

Measurement Techniques: 

The rabbit surveys are conducted at night using spotlights positioned out each side of a pick-up truck. Surveys began one hour after sunset, when no trace of sunlight or dusk remained. Beginning in 1998, all surveys are conducted on or near the full moon.  

The truck is driven slowly (8-10 miles per hour) along the 21.5 mile circuit. Two (or more) observers stand in the bed and scan the left and right sides (respectively) of the road with spotlights, while the driver keeps watch for rabbits directly in front of the vehicle.  

During 1992, the spotlights were Q-Beam 500,000 candlepower spotting lights, with both flood and spot settings (spot settings were used during the rabbit sampling).  From 1993 through 1996, Q-Beam spotlights with 1,000,000 candlepower were used.  In 1997, new spotlights with 3,000,000 candlepower were used; these lights were set permanently on "flood", but illuminated distances previously reached by the spot settings of the less-powerful spotlights. SInce 2002, 2,000,000,000 candlepower spotlight gave been used.

In addition to the spotlights used by the standing observers in the bed of the pickup truck, two spotlights mounted on the pillar posts of the truck's cab are turned on and set for the roadsides ahead of the truck; these lights, coupled with the high-beam setting of the truck's headlights, illuminate the road in front of the truck for approximately 100 meters. When a rabbit is observed, one person's spotlight illuminates the spot at which the rabbit was first seen.  The second person's spotlight tracks the rabbit so it is not counted twice.  A meter tape is walked out from the center of the truck bed (i.e., the center of the road) perpendicular to the location at which the rabbit was first observed.  That distance is measured and recorded to the nearest meter. If a rabbit is observed in the middle of the road, the distance is recorded as zero.  

Beginning in Jan. 2000, perpendicular distances are measured using a laser range finder, with an accuracy of 1 meter. Accuracy level is checked prior to sampling. Generally, rabbits within 100 meters of the road can be seen relatively clearly with all three types of spotlights.

Other data recorded includes (1) the odometer reading in miles from the beginning of the sample at Black Butte (odometers are reset to zero at the start of the sample), (2) whether the rabbit was on the left or right side of the road, and (3) the species of rabbit.  Incidental data on weather conditions is also noted including presence of clouds and moon, time at which the survey was begun, and times at which each leg was begun and finished. The names of the people on the sampling crew are also recorded. 

Analytical Procedures:  

Perpendicular distance data are entered into Program DISTANCE to estimate the total density of rabbits in the study area. Values are computed as numbers of individuals per square kilometer.

Instrumentation: 

2,000,000,000 candlepower Q-Beam spotlights.

Maintenance: 

File created 23 Nov. 1992 - SM

1-30-95: 1-23-95 data entered by Rosemary Vigil.9-11-97: doc file created by Robert R. Parmenter 9-11-97: 4-25-95 through 8-4-97 data entered by Robert R. Parmenter 9-19-97: archived by Gregg MacKeigan as rabbit_survey_92-97.dbf. 10-29-97: data for 10-27-97 entered and checked by Robert R. Parmenter 2-6-00: data for 1998, 1999, and Jan. 2000 entered and checked by Robert R. Parmenter. 12-25-00: data for April, July, and October 2000 entered and checked by Robert R. Parmenter. 2-6-01: data for February 2001 entered and checked by Robert R. Parmenter. 2-5-02: data for April, July and October 2001, and January 2002, entered and checked by Robert R. Parmenter. 6-26-02: data for April, 2002, entered and checked by Robert R. Parmenter. 7-24-02: data for July, 2002, entered and checked by Robert R. Parmenter. 10-25-02: data for October, 2002, entered and checked by Robert R. Parmenter. 12-30-05: data for 2003 and 2004 entered and checked, and final edits to metadata file made by Robert R. Parmenter. doc

Additional information: 

Dates of collection vary in some years, but sampling is generally conducted in January, April, July, and October.

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