Comparison of Northern Bobwhite Chick Fecal and Crop Analyses

Transcription

1 National Qail Symposim Proceedings Volme 5 Article Comparison of Northern Bobwhite Chick Fecal and Crop Analyses Kristen Utz University of Georgia John P. Carroll University of Georgia Steven J. Moreby The Game Conservancy Trst Follow this and additional works at: Recommended Citation Utz Kristen; Carroll John P.; and Moreby Steven J. (22) "Comparison of Northern Bobwhite Chick Fecal and Crop Analyses" National Qail Symposim Proceedings: Vol. 5 Article 48. Available at: This Qail Physiology and Genetics is broght to yo for free and open access by Trace: Tennessee Research and Creative Exchange. It has been accepted for inclsion in National Qail Symposim Proceedings by an athorized editor of Trace: Tennessee Research and Creative Exchange. For more information please contact trace@tk.ed.

2 Utz et al.: Comparison of Northern Bobwhite Chick Fecal and Crop Analyses COMPARISON OF NORTHERN BOBWHITE CHICK FECAL AND CROP ANALYSES Kristen Utz Daniel B. Warnell School of Forest Resorces University of Georgia Athens GA 362 USA John P. Carroll Daniel B. Warnell School of Forest Resorces University of Georgia Athens GA 362 USA Stephen J. Moreby The Game Conservancy Trst Fordingbridge Hampshire SP6 IEF United Kingdom ABSTRACT Impacts of modem agricltre on gamebird brood ecology have been stdied in a nmber of species. One common factor cited has been the decline in available invertebrate food available to foraging chicks. In the United Kingdom assessment of chick diet has been accomplished mainly throgh fecal analysis of wild chicks whereas in North America crop analysis of hman-imprinted chicks has become a commonly applied techniqe. We compared reslts of both techniqes on grops of hman-imprinted northern bobwhite (Colins virginians) chicks to determine if these different techniqes provide similar reslts. Chicks were allowed to forage in grops of 6-8 in cotton fields with varios cover crops. We ethanized half the chicks for crop analysis and isolated the other half of the chicks for 2 hors to collect feces. We fond a positive relationship between total nmber of invertebrates/chick in crops and feces (P = R 2 =.5). However among important chick-food Orders the relationship varied greatly: Coleoptera (P = R 2 =.34) Homoptera (P < R 2 =.4) and Hymenoptera (P =.8 R 2 =.5). Or reslts sggest that there is a positive relationship between the 2 techniqes bt that composition of the diet relative to what foods might be available in a particlar site cold be biased. We sggest more detailed research on techniqe development and standardization of techniqes for assessing this important component of bobwhite life history. Citation: Utz K J. P. Carroll and S. J. Moreby. 2. Comparison of northern bobwhite chick crop and fecal analyses. Pages in S. J. DeMaso W. P. Kvlesky Jr E Hernandez M. E. Berger eds. Qail V: Proceedings of the Fifth National Qail Symposim Texas Parks and Wildlife Department Astin TX. Key words: brood habitat chicks Colins virginians fecal analysis Georgia insects northern bobwhite INTRODUCTION Gamebird biologists have developed a nmber of techniqes to assess qality of brood habitat. For several species especially those inhabiting agricltral ecosystems a primary consideration has been to assess the importance of the invertebrate commnity to provide food resorces. In northern bobwhites it has been demonstrated in nmeros stdies that there is a significant link between invertebrate nmbers and composition and chick ecology (Handley 93 Hrst 972 Potts 986 Jackson et al. 987 Sotherton and Moreby 992 DeVos and Meller 993 Palmer 995). Nmeros techniqes have been sed over the years to assess nmbers and types of invertebrates available to gamebird chicks in the field. Insect sampling techniqes commonly employed inclde vacm samplers (e.g D-Vac systems) pit-fall trapping and sweep-netting (Hrst 972 Brger et al. 993). Biologists have also employed more direct measres sing data derived directly from chicks inclding gt and fecal analysis (Moreby 988 Palmer 995). Hmanimprinted chicks have also been employed to assess invertebrate availability (Kimmel and Healy 987). Pblished by Trace: Tennessee Research and Creative Exchange Some researchers sing hman-imprinted chicks have observed and identified foods consmed by chicks (Erpelding et al. 987) whereas others have sed esophageal strictre and/or gt analysis (Palmer 995). Palmer (995) arged that mechanical sampling devices have limitations becase even if they provide an nbiased sample of insects in a particlar habitat they do not actally provide any estimate of those invertebrates available to or selected by gamebird chicks. Frther almost all other techniqes that are applied commonly have ntested assmptions and/or limitations in their application to gamebird management (Palmer 995). Use of qail chicks as the sampling tool offers the best opportnity for assessing habitat; however this techniqe has logistical problems. For example wild broods wold provide the best opportnity to assess foods consmed bt sampling techniqes reqire that this be done in an indirect way. Typically this has been done by sampling feces collected in the wild or by captring wild chicks to extract crops and gizzards. Since wild chicks can be difficlt to obtain especially in ecosystems where biologists are trying to nderstand low poplation densities the se of hman-imprinted chicks has been viewed as a viable compro-

3 National Qail Symposim Proceedings Vol. 5 [22] Art UTZ ET AL. mise. Previos research done on wild broods sing fecal analysis and hman-imprinted qail sing crops sggests that there is predictive vale to both techniqes (Sotherton and Moreby 992 Palmer 995). As part of a research project investigating cotton cropping systems and qail brood habitat we compared 2 commonly sed techniqes (crop and fecal analysis) to examine invertebrate abndance in brood habitat. STUDY AREA The stdy was condcted in the Upper Coastal Plain ecological region in Jefferson and Johnson conties Georgia. This region is dominated by row crop agricltre and pine plantations. Dominant crops were cotton peants and com. Forests consisted of hardwoods and loblolly pines (Pins taeda). METHODS Stdy Design The stdy consisted of 2 dplicate fields (abot I ha) with each field divided into 4 treatments. Treatments consisted of: ) conventional tillage where cotton is tilled with a standard pesticide regime 2) conservation tillage type A where fields are strip-tilled and winter wheat is sed as a cover crop with a standard pesticide regime 3) conservation tillage type B where fields are strip-tilled and clover and winter wheat are sed as cover crops with a standard pesticide regime and 4) clover-strip tillage where fields are strip-tilled and clover is sed as a cover crop bt no insecticides and minimal herbicides are sprayed on the field. A randomized complete block design was sed to redce variation among the fields. Imprinting We imprinted the chicks following Palmer (995). Imprinting was sed to allow the qail chicks to establish a bond with the researcher. We cold then allow chicks to forage in a habitat for controlled periods of time thereby standardizing or sampling techniqes. Two-hndred fifty qail eggs for each trial were obtained from a private breeder and were mechanically incbated for 2-23 days. On the last 2 days before hatching we whistled to them to begin the imprinting process. As they hatched the chicks were allowed to dry and were then placed in a brooder where the temperatre was maintained at 35 C. They were fed commercial chick starter. Dring the first 2 days after hatch the qail handler spent p to 5 hors per day establishing a bond with the chicks sing whistling and imitating hen calls. Approximately 3 chicks were imprinted in Jne 2 in Jly 2 and 7 in Agst 2. After imprinting we allowed chicks to forage at least once in each cotton cropping system. This allowed the chicks to practice foraging at each crop type LL. y =.5.U7x ll: 5 R 2 =.5.!:! 4 i:: L.Cl :::: z Fig.. Relationship between invertebrates conted in the crops and feces of bobwhite grops (n = 24) foraged in cotton fields in Georgia dring 2. The solid line is the least sqared regression of the data and dashed line represents a theoretical : relationship. and to become familiar with the handler before the final trials. This was done for abot 5 days. Data Collection Field trials occrred when the chicks were 8- days old. Feed was removed 2 hors before the field trials to ensre chicks were hngry. Grops of 6-8 chicks were allowed to forage simltaneosly on each of the field types for 3 mintes. After foraging half of the chicks were collected in boxes for fecal collection while the other half were sacrificed sing a carbon dioxide chamber. De to low hatch sccess the sample size in Jly ( chicks) was less than Jne (3 chicks) and Agst (7 chicks). Therefore 6 chicks were sed per grop instead of 8. Chicks that were sed for fecal collection were isolated in divided brooders. Feces were collected for 2 hors and placed in vials containing 7% ethanol. Insect contents were identified in the feces and were categorized to taxonomic Order. We conted insects in feces following Moreby (988). Use of qail chicks in this stdy followed protocols. approved by the University of Georgia (IACUC Animal Use Permit #A l). Data Analysis We sed regression analysis to assess the relationship and predictive ability of crop and fecal analysis. RESULTS We tested grops of chicks in a total of 24 trials (3 time periods and 2 blocks with 4 cover types in each block). In most cases there were 8 chicks in each grop. Or reslts sggest a positive relationship in nmbers of insects consmed between fecal and crop contents (F = df P = R 2 =.5) (Fig. ). 2

4 2.5 Utz et al.: Comparison of Northern Bobwhite Chick Fecal and Crop Analyses BOBWHITE CHICK FECAL AND CROP ANALYSES Ill CD 4 y = CD 3.5 R 2 =.34 LL.II: 3.!:?.c "'i:: 2 CD.c E.5 :::s z Fig. 2. Relationship between Coleoptera nmbers conted in the crops and feces of bobwhite grops (n = 24) foraged in cotton fields in Georgia dring 2. The solid line is the least sqared regression of the data and dashed line represents a theoretical : relationship. Among Orders comprising important chick foods relationships between the two techniqes were variable. Comparison of feces and crop in Order Coleoptera sggested a positive relationship (F = df P = R 2 =.34 ); however the regression sggested that 5 insects wold be detected in the crop for each one detected in the feces (Fig. 2). Comparison of crops and feces in Order Homoptera sggested a positive relationship (F = df P < R 2 =.4). For this Order we were more likely to find insects in the feces rather than the crops (Fig. 3 ). In the Order Hymenoptera we fond no relationship between the nmbers fond in the crops and feces (F = df P =.8 R 2 =.5) (Fig. 4). DISCUSSION Or reslts sggest that the total nmbers of insects per chick in the feces and crop were significantly correlated. This is an important finding becase stdying fecal contents alone wold be a non-destrctive means of stdying brood habitat withot having to sacrifice the chicks for gt samples. However it is apparent from this comparison that insects available to and/or selected by qail cold yield significantly different reslts depending on the techniqe chosen. For instance the Order Coleoptera consists of beetles which contain hard shells and moth parts. The easily identifiable parts that are difficlt for a chick to digest allow easy identification in the feces. However or reslts also sggest that these insects might be retained in the gt longer than the 2 hors we collected feces. Most of the insects in the Order Hymenoptera consmed by chicks in or stdy were ants (Formicidae ). These have soft bodies and hard moth-parts therefore might pass very qickly throgh the gt yet be easily identified. Therefore both techniqes have potential biases associated with the relative passage and digestion of varios invertebrates. Other factors sch as behavioral and/or physiological characteristics of the chicks cold affect reslts. For example when forag- 4. II) a 3 a LL -.c: 2.::: a.c E :::: z R 2 =.4 y = 5.693x Nmber/Chick Crop Fig. 3. Relationship between Homoptera nmbers conted in the crops and feces of bobwhite grops (n = 24) foraged in cotton fields in Georgia dring 2. The solid line is the least sqared regression of the data and dashed line represents a theoretical : relationship. ing chicks with empty crops chicks might fill and pass crop contents faster than the 3 mintes sed in this stdy. Ambient temperatre dring foraging periods for these animals with limited thermoreglatory ability might also impact food passage rates and levels of digestion. A weakness in or experiment is the possibility that there were significant differences in types of invertebrates consmed by the sbsamples of chicks sed for each techniqe. This is difficlt to test bt we fond or chicks foraged in relatively tight grops and were randomly assigned to a sampling method. Therefore we believe that there shold be little bias in foods consmed among chicks within grops. II) a a LL R 2 =.5 " " :c.5 3 y =..565x ::: a.c E :::: z Fig. 4. Relationship between Hymenoptera conted in the crops and feces of bobwhite grops (n = 24) foraged in cotton fields in Georgia dring 2. The solid line is the least sqared regression of the data and dashed line represents a theoretical : relationship. Pblished by Trace: Tennessee Research and Creative Exchange 22 3

5 National Qail Symposim Proceedings Vol. 5 [22] Art UTZ ET AL. MANAGEMENT IMPLICATIONS Or data sggest that 2 commonly employed techniqes provide similar reslts when assessing total nmbers of invertebrates consmed by bobwhite chicks. However there were marked differences at the Order level. These reslts sggest that we need to investigate in more detail the assmptions we make with or invertebrate sampling techniqes especially those related to assessing habitat qality. ACKNOWLEDGMENTS Fnding was provided by Qail Unlimited Monsanto Corp United States Department of Agricltre Natral Resorces Conservation Service Central Georgia Soil and Water Conservation District and the University of Georgia Daniel B. Warnell School of Forest Resorces and McIntyre-Stennis Project GE- -MS. We thank H. Venter D. Maidens R. Franklin and M. Cooper for field assistance. Mr. A. Walker provided mch logistical spport. We thank T. Harrington and R. Hamrick for assistance with statistical analyses. LITERATURE CITED Brger L. W Jr E. W. Krzejeski T. V. Dailey and M. R. Ryan Relative invertebrate abndance and biomass in Conservation Reserve Program plantings in northern Missori. Proceedings of the National Qail Symposim 3: 2-8. DeVos T and B. S. Meller Reprodctive ecology of northern bobwhite in north Florida. Proceedings of the National Qail Symposim 3:92-. Erpelding R R.. Kimmel and D. J. Lockman Foods and feeding behavior of yor gray partridge in Minnesota. Pages 7-3 in R.. Kimmel J. W. Schlz and G. J. Mitchell eds. Perdix IV: Gray Partridge Workshop. Minnesota Department of Natral Resorces Madelia. Handley C Food of the yong. Pages in H. L. Stoddard. The bobwhite qail: its habits preservation and increase. Charles Scribner's Sons New York New York. Hrst G. A Insects and bobwhite qail brood habitat management. Proceedings of the National Qail Symposim : Jackson J. R G. A. Hrst and E. A. Glesing Abndance and selection of invertebrates by northern bobwhite chicks. Proceedings of Annal Conference of Sotheastern Association of Fish and Wildlife Agencies 4:33-3. Kimmel R. and W. M. Healy Imprinting: a techniqe for wildlife research. Pages in R.. Kimmel J. W. Schlz and G. J. Mitchell eds. Perdix IV: Gray Partridge Workshop. Minnesota Department of Natral Resorces Madelia. Moreby S. J An aid to identification of arthropod fragments in the feces of gamebird chicks (Galliformes) Ibis 3: Palmer W. E Effects of modern pesticides and farming systems on northern bobwhite qail ecology. Dissertation. North Carolina State University Raleigh. Potts G. R The partridge: pesticides predation and conservation. Collins London United Kingdom. Sotherton N. W and S. J. Moreby The importance of beneficial arthropods other than natral enemies in cereals. Interpretation of Pesticide Effects on Beneficial Arthropods. Aspects of Applied Biology 3: