Document 5D6oG5XxVg2w6vJO3ZYnQyBnR

Organochlorine Residues in Aquatic Birds in the Canadian Prairie Provinces Kbei Vermeer Ctnidian Wildlife Service, Edmonton, Alberti Lincoln M. Reynolds Ontario Research Foundation, Sheridan Park, Ontario Abstract. A survey was conducted of organochlorine residues in 21 aquatic bird species at 31 Iocslions In Alberta, Saskatchewan and Manitoba. As DOT and ODD residue levels from analyses without PCB separation proved to be unreliable, they were omitted from the results. DDE and dieidrln levels were hither in csis of leridi and flsh<eatin| birds than In those of leete and ducks. presumably reflectint different trophic levels between those two (roups of birds. Interspecific differences of DDE, dieldrin, HE and a BHC residues observed in larids end Asheatlnt birds at the earns breading localities may reflect interspecific differences of feeding habits. DDE, dieldrin and PCB levels may be predicted in tissues of California Oull females when known in their eggs. Residue levels in egg* closely resembled those In the livers of females at the time of laying. Shell thickness was significantly and Inversely corre lated with the concentration of DDE In 40 Orsat Blue Heron eggs from Alberta, but no significant correlation was found between the concentration of PCBs and shell thickness in those eggs. Introduction It hag been shown that fish-eating birds in England contained greater average organo chlorine residues than any other group of birds examined (Moore and Walker, 1964). J. O. Keith (1966) found that fish-eating birds in California accumulated large residues of insecti cides in their body tissues. The results of a study on reproductive success in a Wisconsin population of Herring Gulls, Lams argenialus, contaminated with DDT suggested that DDT residues were responsible for the low hatching success of eggs (J. A. Keith, 1966). Reduced shell thickness has been found to be correlated with the amount of DDE in the egg contents of raptors (Hickey and Anderson, 1968;Fyfe el at., 1969) and fish-eating birds (Hickey and Ander son, 1968; Anderson era/., 1969). Experimental studies with Mallards, Anas platyrhynchos, showed that DDE can reduce thickness and cause cracking of eggshells (Heath et at., 1969). For these reasons, and as little is known about the extent of organochlorine residues pre sent in aquatic birds of the Canadian prairie provinces, a survey was conducted to determine the type and quantity of organochlorine residues present in aquatic birds, particularly larids and fish-eating birds, in Alberta, Saskatchewan, and Manitoba. Eggs were chosen at samples to be analyzed for organochlorine residues as they are easy to collect and constitute distinct units of comparison between species. Methods Seventy composite samples of eggs were col lected during egg-laying and Incubation from aquatic birds in Alberta and Saskatchewan in 1968 and thirty composite samples of eggs were collected in Saskatchewan and Manitoba in 1969. Each composite sample consisted of 10 eggs, representing one egg from each of 10 nests of the same species. Composite rather than individual samples were collected to re duce costs of analyses. Additionally, in 1969 ten individual egg samples were taken from Common Terns, Sttrna hirundo, and Doublecrested Cormorants, Phalacrocorax aUritus, and 40 individual egg samples were taken from Great Blue Herons, Ardea herodias, to assess variations of pesticide residue levels within nesting colonies. The egg shells of the Great Blue Herons were dried at room temperature for 416 months before their thickness was measured in order to relate shell thickness to DDE levels in those eggs. Thickness in each case represents the shell itself plus the dried egg membranes. Ten adult California Gulls, Lams ccdijornicus, were also collected on an Edmon ton garbage dump upon arrival during the second week of April, 1969. Ten females of that species and their eggs were taken from their nests at Joseph and Miquelon lakes, 20 and 27 miles respectively from the first collection site, during egg-laying and their first week of incu- 117 HONS 097776 118 The Canadian Field-Naturalist Vol. 84 Tarlb l,--DDT and DDD residue levels in ppm wet weight More nud after PCB separation in tissues and etff* of female California Gulls. Mean DOT Mean DDD No. ample Sam. Before After % Before After % Abdom. (at Liver Erst 10 10 10 10 10 2.099 0.156 0.066 0.022 0.090 0.577 28 0.025 16 0.002 5 0.001 5 0.028 51 1.891 0.157 0.072 0.025 0.075 0.064 0.025 0.009 0.001 ND 5 16 15 4 0 ND * tone detected > < 0,( Ml ppm bttlon In tho first week of May, 1969. Gull tissue? and eggs were analyzed for the purpose of comparing pesticide residue levels between arriving and incubating gulls as well as between incubating females and their own eggs. One type of tissue analysed was fat, taken from the abdominal cavities of the guilt. The contents of eggs and bird tissues were stored in glass jars and preserved by freezing. Laboratory Analysts For extraction of the organochlorine residues. the frozen egg sample was thawed out and homogenized in a Waring Blender. An aliquot (2-5 g) of the blend was weighed into a 50 ml beaker to the nearest milligram and dried in a vacuum oven at 45C with slight vacuum to constant weight (approximately 36 hours needed). The per cent moisture was then calculated from the difference in weights. After constant weight was obtained, the dried sample was broken up by adding 5-10 g an hydrous Na. SO, and grinding with a flattened glass rod. The dried material was removed from the sides and bottom of the beakers by grinding and scraping. The mixture was pourtnl into a Soxhlet thimble and the beaker rinsed several times with ether : n-hexane (1:1). A glass wool plug was used to cover the sample in the thimble which was then extracted in a Soxhlet apparatus for 2 hours, using about 150 ml of 1:1 ether-hexane mixture at a rate of 10 siphonings per hour. After extraction, the solvent was removed In a flash evaporator and the dried flask was weighed. The per cent fat wu calculated from the difference in weights. v r oo ..nTz3o*e.ezTT x Figure 1. Relationship between DDT, before PCB separation, and PCB levels In ppm wet weltbt ( p <0.01). MOWS 097777 \ > f ' TaI* 1-Mw wet-1 riifci p%jm rfPPBla --Itr mmpkm*WhimHe fa tfa 1970 V ermeer and R eynolds: Pesticide Residues in B irds MONS 097778 o HONS 097779 T he Canadian Field-Naturalist Vol. *4 1970 Vermeer and Reynolds: Pesticide Residues in Biros 121 ppm ODD Fiounfi 2. Relationship between DDD, before PCB separation, and PCB levels in ppm wet weight. Table 4. -- Mean wet-weight ppm residues of HE in composite samples of 10 aquatic bird eggs in the prairie * provinces Sample location California Cull Ring-billed Gull Herring Gull Doublecrested Cormor. White Pelican Great Blue Heron Mallard 3. L. Therien Lake 4. Chip Lake 5. Miquelon Lake 6. Battle Kiv. (Wetaskiwvn) 7. Jamieson Lake 12. Belly Riv. (Glenwoodville) *2. Old Wives Lake 23. Cypress L. 24. Talbot L. 25. Moose L. 2(1. l^tkc Winnipegosih 27. Knwinaw Lake 2t. Pelican L. 29. Lake Winnipcg (St.. Martin la.) 30. Dog (,alce 31. take Man- itoba 0.015 0.020 0.027 0.009 0.043 0.2*6 (0.008)* 0.043 0.127 0.142 0.035 0.167 0.146 0.043 0.134 0.114 0.016 0.033 0.015 0.032 0.075 0.022 0.022 0.074 0.028 0.044 ND 0.018 0.015 0.010 0.022 0.022 0.023 0.018 Q.0U 0.017 0.071 0.007 0.015 0.040 0.009 0.902 (0.067)* MlvplncMor. HONS 097780 I 122 The Canadian Field-Naturalist Vol. *4 Tabmc 5.--Menu wet-weight ppm residue. of 0-BHC in composite samples of 10 aquatic bird eggs in the prairie province* Sample location California Cull Ring-billed Cull Herring Cull Double* crested Connor. White Pelican Great Blue Heron Mallard 3. L. Therien 4. Chip Lake S. Miquelon Lake ND 6. Battle Rlv, (WeUakiwin) 7. Jemie*on Lake 12. Belly Rlv. (Gtenwoodville) 22. Old Wive* Lake ND 23. Cyore** L. ND 24. Talbot L. 23. Mooee L. 26. Lake Win. nipeiosie 27. Kawinaw 29. Lake Win. nipet (St. ND ND ND ND 0.040 0.026 30. Dog Lake 31. Lake Man. ND ND ND ND ND 0.033 0-065 ND ND 0.230 0.176 0.167 0.170 0.260 0.206 0.200 ND ND ND ND ND 6.032 ND ND ND ND 0.062 0.008 0.020 0.028 ND. ND The ft retidue was dissolved in 150 ml of J% benzene in acetone and the solution was cleaned-up by cold precipitation, essentially according to the method of McCully and Mc Kinley (1964). The solution was chilled to --70*C and stirred for 35 minutes in a dry icemethanol cold bath. The mixture was then FlOUNB 3. Sample location* of aquatic bird egg* in Albert^ Saskatchewan and Manitoba. filtered through a carbon-ceiite (2 g: 10 g) pad at --70C dried with Na. SO,, concentrated and made to a volume of 5 ml with hexane. Addi tional cleanup was effected by use of a Florisil column and the cleaned-up extract was analysed for pesticide residues by gas liquid chromato graphy-electron capture (GLC-EC) technique with parameters as described by Reynolds (1969). The compounds screened for were lindane, heptachlor, aldrin, kelthane, DDE, dieldrin, DDD, o,p'-DDT, p,p'-DDT, methoxychlor, endrin and tedion in 1968 and in addition heptachlor epoxide (HE) and benzene hexachloride (a-, (3-, and y-BHC) in 1969. No corrections were made for pesticide losses during the extraction and cleanup processes, although recovery studies for 8 of the more common pesticides showed an average loss of about 10%. Confirmation of specific residues was made by use of more polar phase GLC columns, derivatization and use of characteristic MONS 097781 1970 Vermeer and Reynolds: Pesticide Residues in Birds 121 OLC retention times of the derivatives, and by moisture and fat of each pooled egg sample is thin layer chromatography where possible. shown in the appendix. A number of samples were analysed for polychlorobiphcnyls (PCBs) as these com Results and Discussion pounds interfere with the orgitnocltlorine pesti Survey of Pooled Egp Samples cide analyses. The PCBs were separated from The numbers in Figure 3 denote the locations the organochlorine pesticides by differential where the egg samples were collected and re elution from a Fiorisil column and estimated by late to those in Tables 2, 3, 4, and 3. Samples the methed of Reynolds (in press). The PCB were taken in Alberta and Saskatchewan in values reported are based on Aroclor 1254 and 1968, except for Cypress and Old Wives Lakes, are the averages of the calculation for peaks and at those two lakes and in Manitoba in No. 8 and 10, two of the major peaks in the 1969. Collections were made at certain loca PCB commercial mixture. It can be seen that tions in Alberta in both years. Table 2 shows DDT and DDD residue levels obtained in 30 the DDE residue levels present in aquatic bird California Oull tissues without prior PCB sep eggs. The eggs of larids (except Franklin's aration, are unreliable (Table 1). An Increase Cull, Larus plplxcan) and those of fish-eating in those levels can be significantly correlated birds such as the Double-crested Cormorant, with a greater PCB contamination (Figures 1 White Pelican, Pelecanus erylhrorhynchos, Great and 2). As the DDT and DDD levels obtained Blue Heron, and Western Grebe, Aechmophorus without PCB separation are unreliable and as occidentalIs, contained the highest DDE levels, they constituted only a small fraction of the while waterfowl egg levels were generally the total DDT plus metabolite contamination, they lowest. This difference may simply reflect feed have been omitted from the results. ing habits and biological magnification of DDE, The DDE values presented may include smalt (or the plant and small animal food of the contributions from PCBs since DDE is not waterfowl can be reliably expected to contain separated from a minor PCB interfering peak. lower concentrations of DDE than the larger However, if the GLC pattern of a sample animal food of the larids and fish-eating birds. extract (prior to PCB separation on Fiorisil) Within larids, the generally higher DDE I shows high "apparent" DDE with little or no residue levels in the eggs of California Gulls DDD and DDT present, then all or most of than in those of Ring-billed Gulls, Larus I the apparent DDE is probably "true" DDE. It detawarensis, may also result from a dif I should be noted that almost all the samples, ference in diet, since California Gulls eat on with the exception of the fat tissues, showed the average larger rodents and are greater less than one ppm DDT or DDD prior to PCB scavengers than Ring-billed Gulls (Vermeer, separation, thus indicating that PCB contribu 1967). tions to the DDE values are likely to be small. For Franklin's Gulls, the average DDE re No standard method was found in the litera sidue level found in the present study is ture to represent quantities of organochlorine similar to the 0.462 ppm wet weight reported residues in tissues. In this paper, the pesticide for 30 eggs of Franklin's Gulls at Hay Lakes, residues are shown in ppm wet weight as most Alberta, in 1966 (Guay, 1968). The relatively articles relating to pesticides appear to follow low residue levels in the eggs of Franklin's this procedure. As loss of moisture from eggs Gulls may be related to their dominantly insect during incubation tends to concentrate organo ivorous diet. Guay (1968) found that the chlorine residues in the growing embryo, and as Franklin's Gull diet consisted of 88% insects. there are interspecific differences in the moisture No vertebrates were present in the stomachs of percentage of eggs it may be more accurate to the 27 Franklin's Gulls examined by him. The present residues on a dry-weight basis. For those diet of California and Ring-billed Gulls in con who want to convert the residues from wet to trast includes large quantities of rodents (Ver dry or lipid weight in ppm, the percentage meer, 1967). MUNS 09 770 124 The Canadian Field-Naturalist Vol. 4 Taclk 6.--Menu. nnd 93% confidence interval. of organochlorine insecticide reeiduei in tiHUee of Cnlifornin Guile collected in the vicinity of Edmonton; 10 during spring arrival and 10 during egg-laying in 1949 Tlarue nalited Tima collected Abdominal fat Uvar Brain Arrival Egg-laying Arrival Egg-lnylng Arrival Egg-laying HE observed in < 3 samples. % Fat In tluue 67.8*7.4 68.6*8.8 4.1*1.0 4.0*0.6 7.3*0,4 6.9*0.3 Retlduea in ppm wet weight DDE Dieldrin HE 211.62*141.33 134.tl* 91.20 7.73* 6.33 3.37* 3.29 2.14* 1.43 1.31* 0.74 1.01*0.43 1.16*0.40 0.09*0.03 0.08*0.04 0.02*0.01 0.02*0.01 0.68*1.31 0,31*0.23 0.02*0 02 0.01*0.01 0.0007* 0.0011* The Herring Gull, like the California Gull, b g scavenger, but the former appears to eat more fish in its inland habitat (Mendall, 1939; Lud wig, 1962). The DDE residue levels observed In the eggs of this species at the large Manitoba lakes may be a reflection of its diet. J. A. Keith (1966) associated Herring Gull egg levels aver aging 202 ppm wet-weight DDE with excep tionally low hatching success in northern Lake Michigan, and the lower 95% confidence limit of this average was 122 ppm, seven times higher than the highest Herring Gull level reported here. No quantitative data on the food habits of Common Terns, in the prairie pro vinces are available. The diet of this species on the Maine coast chiefly consists of fish and crustaceans (Mendall, 1935). The DDE levels in the eggs of this species at different breeding locations appear to vary more than in the other larids. The higher residue leveb found in the eggs of Double-crested Cormorants than in those of White Pelicans may be related to their different feeding habits. White Pelicans scoop fish from the water surface (Hall, 1925) while Doublecrested Cormorants obtain fish by diving (Bar tholomew, 1942). Anderson f al. (1969) found similar differences in DDE residues be tween those two species in Minnesota, Wiscon sin, North Dakota, Manitoba and Saskatche wan. They explain them as being a result of dissimilar non-breeding area exposures. Ac cording to their calculations, based on informa tion from Bent (1922), Lewb (1929), Mendall (1936), and refuge personnel, pelicans arrive on the average on April 10 and cormorants on May 3. However, Lewis (1929: 14) states that Table 7.--Variation of DDE reiiduei in ppm wet weight in individual aamplei of 10 aquatic bird esge In Alberta in 1909. Specie* Great Blue Heron Great Blue Heron Great Blue Heron Great Blue Heron Common Tern California Gull . Double-created Cormorant Where Collected Belly River (Glenwoodville) Battle River (Wetaakiwin) jamieeon Lake Chip Lake Chip Lake Miquelon and lotoph Lake* L. Tnerien Lake Mean 9.95 3.71 6.61 37.01 6.38 7.51 3.57 Range 1.5 - 24.0 1.4 - 13.5 1.0 - 31.8 0.7 - 234.4 1.2 - 33.3 2.1 - 20.2 1.5 - 6.4 Coefficient of Variation 61.83 69.96 138.68 197.73 151.93 91.09 41.65 HONS 097783 1970 Vbrmbbr and Reynolds: Pesticide Residues in Birds 125 cormorants In Manitoba may arrive at the end of March or early April. From eight average arrival dates each (Lewis 1929: id), we calculate that cormorants arrive on average in Minnesota, Wisconsin and North Dakota on April 17 and in Manitoba on April 24. One of us (KV) watched the spring arrival of cormorants at Cypress Lake, Saskatchewan, in 1969 and at Lake Newell, Alberta, in 1968 and 1969. Cormorants occupied their nesting grounds by mid-April, even before ice disap peared from those lakes, and initiated egg-laying during the last week of April (Vermeer, 1970; in press). KV also observed little or no inter specific difference in hatching dates where the two species nested together in large numbers in the Canadian prairie provinces. Hence it appears that the interspecific differences in DDE residues cannot be explained on the basis of dissimilar spring arrival dates. Different food habits on the breeding and/or non-breeding grounds is a more Ukely explanation for dissimilar DDE contamination of the two species. The dleldrin residue levels in the aquatic bird eggs are shown in Table 3. Although the dieldrin levels are not as high as those of DDT compounds, their effects are not lest serious. DeWitt el el. (1960) tested the toxicity of 21 Insecticides to Bobwhite Quail, Colima vlr/Momu, and found dieldrin to be 14 times more toxic than DDT. At has been observed for the DDE residues, the eggs of larids and fish-eating birds contain more dieldrin than those of water fowl, while cormorants appear to be more contaminated than pelicans. HE is of similar toxicity as dieldrin to birds (Moore, 196S). HE is rapidly metabolized from heptachlor and hence die latter it rarely Fiousf. 4. Relationship! of orgenochtorine residue levels within pairs of eggs from 10 California Oull cluiehei; points being intersections of pair vslues. MONS 097784 126 The Canadian Field-Naturalist Vol. 84 TaRLR 8. Meant and 95% confidence intervale of organochlorine ineecticide residues in tissues and single eggs of 10 California Gull females at Miquelon and Joseph Lakes, Alberta in 1969. Par cant ppm wet weight Tissues Fat Non.fat DOE (water axel.) Dieldrin HE Abdominal fat Ovary & Brain 66.64:8.8 11.443.6 7.64:1.0 4.04:0.6 6.940.5 7.44=3.2 17.74:1.1 16.14:0.5 26.34:0.6 13.94:1.1 134.114:91.20 12.564 9.33 7.264: 4.84 5,374: 3.29 1.314: 0.74 1.1640.40 0.154:012 0.0640.03 0.0840.04 0.0240.01 0.31 40.25 0.01940.016 0.01640.015 000940.008 0.001 detected at a residue. But heptachlor was still present where high HE residue levels were found in Ring-billed Oull and Mallard eggs at Cypress Lake (Table 4). It can be seen in Table 5 that Herring and Ring-billed Gulls are more contaminated with HE than cormorants and pelicans, while cormorants in turn have higher average HE levels than pelicans. Table S shows that the cormorants at the lakes in Manitoba are most contaminated with fi BHC residues. Eggs of White Pelicans, Her ring and Ring-billed Gulls contained lower j) BHC residues at the same locations. Perhaps jl BHC is associated with the fish on which cormorants feed. Nothing is known concerning the source of the organochlorine residues in the aquatic birds. We compared residue levels from tissues of 10 California Gulls collected near Edmonton at spring arrival with those of 10 birds of that species taken at Joseph and Miquelon Lakes during egg-laying and the first few days of in cubation in 1969 (Table 6). Although there are no statistically significant changes in residue levels between gulls from those two time per iods, a trend indicates a residue decline of DDE in gulls with the advancing season. This suggests that food taken during spring migra tion or during the winter contained higher levels of DDT or DDE than food taken during the early breeding season. In order to reduce costs of residue analyses, composite egg samples were usually analyzed. However, ten individual eggs, of various species from several localities in Alberta in 1969, were also analyzed to determine DDE residue varia tion within local populations (Table 7). It can be seen that the DDE levels vary considerably within eggs of local breeding populations of Great Blue Herons, California Gulls and Com- Taslb 9.--DDE and dieldrin residue retioe in tissues end single eggs of 10 California Gull females at Joseph and Miquelon Lakes, Alberta in 1969. Tiuua compariaona DDE Mean ratios 4 SE Coefficient of correlation Dieldrin Mean ratios 4 SE Coefficient of correlation Fit/egg tivar/an Braln/efi Ovary/egg 19.643.3 0.8140.12 0.2040.03 1.7640.20 0.9506" 0.9242" 0.9285** 0.8539" 20.342.8 1.4840 29 0.2740.04 2.2140.05 0.8073* 0.3612 0.9366" 0.4327 p < 0.05 *p < 0.01 MQNS 097785 1970 Vbrmebr and Reynolds; Pesticide Residues in Birds 127 Tama 10.--DDE And dicldrin rsaidus ration in tlaiues of 20 California Gulta from Edmonton and Joacph and Mipualon Lalws, Alberta in 1909. TUmi* eompariaon* DDE Mun ratio* * SB Coefficient of correction Dieldrio Mun ratio* * SE Coefficient of correlation Fat/liver Fat/brain Liver/brain 30,8*3,8 107.5*9.4 5.78*0.24 0.9553** 0.9172** 0.9286** 16.4*2.1 73.3*9.8 5.78*0.81 0.4760* 0.8570** 0.7284** mon Tenu. Although one highly contaminated gull, heron or tern may biai a mean composite sample, nevertheleis a pooled temple it better thus a tingle sample at an Indicator ol the degree of organochlorlne contamination of a population. Two Great Blue Heron eggs with 71.0 sod 234.4 DOE residue levels at Chip Lake, lor example, had the highest DDE levels of all aquatic bird eggt collected. If one egg, low In DDB residues, had been sampled, there would be no Indication that tome herons at that looallty were highly contaminated. The variation in individual DDE residue levels was smaller in Double-crested Cormor ants than in Great Blue Herons, California Guilt and Common Terns (Table 7). IntraspecUlc variation In mean DDE residues between differ ent localities was also smaller in cormorants, as well at in pelicans, than in California Gulls, Ring-billed GuUs, Common Terns, Herring and shell thickness In forty Orest Blue Heron e||i from four Albertan heronries in 1969. Gulls and Great Blue Herons (Table 2). This may be related to the almost exclusively fish diet of cormorants as compared to the only partly fish diet of the gulls and herons. Cormor ants probably are more restricted to feeding in deeper waters than terns, which have been observed feeding in very shallow bays is well as in ponds adjacent to the lakes where they nest. Eggs as Indicators . Two eggs of each of 10 clutches of California Gulls at Joseph and Miquelon Lakes were taken in 1969 to determine if organochlorlne residue levels in one egg were representative of those in other eggs laid by the tame female. It can be seen that they were representative as there are highly significant correlations of residue levels between eggs of the tame clutch (Figure 4). A comparison is also made between the organochlorine insecticide residue levels in tissues and in tingle eggs of 10 California Gull females during the egg-laying period (Table 8). As residue levels of eggs and livers were the most alike of all the tissues examined, those in eggs are approximate indicators of those in livers of females at the time of egg-laying. It can be seen that the residue levels in the abdominal (at are significantly higher than those in the ovary, egg, and liver, and that the levels of those tissues in turn are significantly higher than in the brain of the same birds. As organochlorlne residues tend to dissolve and concentrate in fat, the tissues with most fat generally have the highest residue levels. There are exceptions, however, for while the brain contains a significantly higher percentage of fat than the liver, nevertheless the liver has a significantly higher DDE and dield- MONS 097786 128 The Canadian Fibld-Naturalist Vd. 84 Table 11*--Mean* and 95% confidence intervale of PCB reelduet In tleeuee end uncle cue of 10 California Cull fomalaa at Joaeph and Miquelon Laltee, Alberta in 1969. Tarlb 12.--PCB residue ratios in tissues of 10 Cali fornia Gull females and their ess* at Joseph and Mi quelon Lakes, Alberta in 1969. TImum Per cent Non fat Fat (water excluded) PCB in ppm WOt Weight Timuo comparisons F'/*SS LIverTess Braln/esS Ovary/egg Mean ratio * SE 25.45*6.32 1.11*0,27 0.38*0.09 1.67*0.38 Coefficient of correlation O.TS56* 0.6159* 0.6274* 0.7127* sI l 5M l I 68.6*8.8 11.4*1.6 1.8*1.0 4.0*0.6 6.9*0.5 7.4*3.2 17.7*1.1 16.1*0.5 26.3*0.0 13.9*1.1 16.07*6.57 1.22*0.65 0.87*0.39 0.79*0.36 0.29*0.16 rin level than the brain (Table 8). Hence residue comparisons between different tissues on a lipid basis may be sometimes misleading. Residue levels in tissues of California Gull females are compared with those in their eggs (Table 9). As HE residues were not observed in many samples, they have been excluded from the table. Highly significant correlations can be observed in DDE levels between tissues and eggs. Dieidrin levels in the fat and brain alto relate significantly to those in eggs. DDE and dieidrin ratios appear to be of similar magnitude for the same tissue comparisons. Hence, at the correlations are generally signileant, DDE and dieidrin residue levels In tissues of California Gulls at the time of egg laying may be predicted when known in their eggs. They may also be predicted when known in another tissue than eggs (Table 10). PCB residue levels in tissues of California Gull females are also compared with those in their eggs (Tablet 11 and 12). It can be seen that the distribution of PCB residues in tissues follows the same trend as those for DDE, dieldrin and HE (Tablet 8), and that the pattern of PCB residue ratios also follows the same trend at those for DDE and dieidrin (Table 9). Hence PCB residue levels in egg-laying California Guilt may be predicted when known In their igga, and for birds generally, PCB residues may prove to have a tissue distribution pattern sim ilar to the patterns of DDE, dieidrin, and HE. Figure 5 shows a highly significant Inverse correlation between shell thickness and DDE residues in 40 Great Blue Heron eggs from heronries at the Battle River near Wetatkiwln, the Belly River near Glenwoodville, Chip Lake, and Jamieson Lake in Alberta. The DDE re sidues are shown in ppm wet weight to main tain uniform presentation of results. Somewhat better correlations between DDE residues in eggs and egg shell thickness of herons were observed on a dry-weight (r =--0.3741**) and a Upid-weight basis (r =-0.5958**). Hence more significant correlations may be obtained by means of the latter methods when comparing organochlorine residues within the tame tissues. Although a linear regression is shown in Figure 5, the relation between DDE residues in eggs and egg shell thickness was Table 13.--Relation between DDE residue levels and embryonic development in Great Blue Heron efts cot- lected at Chip Lake on May 28, 1969 ppm DDE % water in wet wt. in eggs Condition of embryo in collected egg No. eggs and/* young per nest 0.713 2.17 2.74 4.00 4.62 6.59 til 25.8 78.0 234.4 84 Embryo alive 83 Embryo alive 84 Embryo alive 80 No development (infertile?) 84 Embryo alive 82 Embryo alive 83 Embryo alive 83 Embryo aiivo (pipping) 82 Embryo alive (pipping) 73 Embryo died at early stage 5 4 5 4 S 4 4 5 4 I MONS 097787 1970 Vermeer and Reynolds: Pesticide Residues in Birds 129 illfhlly curvilincor, fitting an exponential curve y m (374.081) (0.9987)*. However, more egg samples with high DDE residue contents are needed to determine whether the actual relation ship between DDE residues in eggs and shell thickness is a curvilinear or a linear one. In contrast with DDE, no significant corre lation (r * -0.1692) was found between shell thickness and PCB residues in the contents of the 40 Great Blue Heron eggs. The heron eggs most contaminated with DDE were found at Chip Lake. It can be seen than an embryo from an egg with 78.0 ppm DDE shows development at least until hatching (Table 15). The embryo from an egg with 234.4 ppm DDE died at an early stage, perhaps as a result of the DDE concentration. Acknowledgments 1 A. Keith was most helpful in his critical review of the manuscript. R. Isbister, J. E. Poison, and S. G. Sealy, assisted in the collec- doo of egg samples. Literature Cited Anderson, D. W,, J. J. Hickey, R. W. Rbcbrougb. D. r. Hughes end R. E. Christensen. 1969. Sig nificance of chlorinsted hydrocarbon residues to breeding pelicans and cormorants. Canadian FieldNaturalist. S3: 91-112. Bartholomew, G. A. 1942. The fishing activity of Double-crested Cormorants in San Francisco Bay. Condor, 44: 13-21. Bent, A. C. 1922. Life histories of North American petrels and pelicans and their aiUea/Order Tublnares and Steganopodes. U.S. National Museum Bulletin 121. 343 pp. DeWItl, I. B* C. M. Menrle, V. A. Adomaitis and W. L. Relcbel. 1960. Pesticidal residues in ani mal tissues. Transactions Twenty-fifth North American Wildlife Conference, 277-283. Fyfe, R. W, 1. Campbell, B. Hayson and K. Hodson. 1969. Regional population declines and organochlorine insecticides in Canadian Prairie Falcons. Canadian Field-Naturalist, 83: 191-200. Cmy, h W. 1968. The breeding biology of Franklln's Gull (Lana plplxan), Unpublished Ph.D. Thesis, University of Alberta, Edmonton, 129 pp. Ilatl, 8. R. 1925. Polleans versus fishes in Pyramid Lake. Condor 27: 147-160. Iteatb, R. C* 9. W. Spann and 3. F. Krcitscr. 1969. Marked DDE impairment of mallard reproduction in controlled studies. Nature 224: 47-48. Hickey, J, I, and D. W. Anderson. 1968. Chlorin ated hydrocarbons end egg shell changes in rap torial and fish-eating birds. Science 162: 271-273. KeHh, I. A. 1966. Reproduction in g population of Herring Gulls (Lontt argentatus) contaminated by DDT. Journul of Applied Ecology, 3, Supple ment: 57-70. Keith, J. O. 1986. Insecticide contamination in wetland habitats and their effect on fish-eating birds. Journal of Applied Ecology, 3, Supplement: 71-85. Lewis, H, F. 1929. The natural history of the Double-crested Cormorant (PhaJocrocowr auriiut aurltus) (Lesson). Ru-Mi-Lou Books, Ottawa. 94 pp. Ludwig, 9. F. 1962. A survey of the gull and tern populations of Lakes Huron, Michigan and Super ior. Jack-Pine Warbler 40: 104-119. McCully, K. A. and W. P. McKinley. 1964. Deter mination of chlorinated pesticide residues in fat by electron capture gas chromatography. Journal of Association of Official Agricultural Chemists 47: 652-659. Mendall, H. L 1933. The relationship of certain Ha birds to the fishing industry of the State of Maine. Bulletin of the Department of Sea and Shore Fisheries, Maine. 27 pp. v 1936. The home-life and economic sta tus of the Double-crested Cormorant (Phalaerocorax aurltut aurliur) (Lesson). University of Maine Studies Second Series, Number 38 (Maine Bulletin 39). 159 pp. ------ --. 1939. Food habits of the Herring Gull in relation to fresh-water game Ashes in Maine. Wilson Bulletin 51: 223-226. Moon, N. W. 1965. Environmental contamination by pesticides, pp. 219-237. In O. T. Goodman tt al,, (Ed.), Ecology and the Industrial Society, Oxford. . and C. H. Walker. 1964. Orgenochlorine insecticide residues In wild birds. Nature, 201: 1072-1073. Reynolds, L. M. 1969. Polychlorobiphenyls (PCB's) and their interference with pesticide residue analysis. Bulletin of Environmental Contamination and Toxi cology 4: 128-143. ' . (In press). Pesticide residue analysis in the presence of polychlorobiphenyls (PCB's). Resi due Reviews 34. Vermeer, K. 1967. A study of two species of gulls, Lotus caUfornicus and L. delawarensis, breed ing in an inland habitat. Unpublished Ph.D. Thesis, University of Alberta, 128 pp. --------- --. 1970. Some aspects of the nesting of Double-crested Cormorants at Cypress Lake, Saskatchewan in 1969; A plea for protection. Blue Jay 28: 11-tJ. ------------ . (In press). Arrival and clutch initia tion of Double-crested Cormorants at Lake Newell, Alberta. Received June 18, 1970 Accepted July 8, 1970 MONS 097788 ! <i T hb Canadian Field-N aturalist ef M awMk 4M <m> 0 the ***** 2L Old Wives Lake 2i. CypeasLake 24. TalketLske 23. Mooes Lake 24. Uk( \Vwip(|NM 27. Kinu Lake AlUnUke . Lake VVaonipc* (Sc Mania U.) 30. Do* Lake 31.Lak* V * 2. CoMLake 4. CMp Lake 4. Battle Stiver rju(WirenuekUiwtUa) 4. OovOa* Lake 9. Stoten Lake 10. Lake Newell 11. Murray Lake 12. Betty River (Gleewaodville) 19. lacfc&sk Lake 20. Haufeford 22. Old Wives Lake 27. Kawiaav Lake 3. L. 7_______ 4. Ckip Lake 3. Miovctoa Lake |0l Lake Hcwdl 19. UckfckLeke 22. Old Wives Lake 2 0.4) H74.i7iEA 75.t4ss 74.4 (4.3 74.1 0.4(, 74.4 (1.4] 77.0 0.3 Bi*:8 73.3 0.0) 79.4(9.1) 79.4(9.0) 79.9'- *' 73.7 74.0 74.4 L4 oloj H.T (9.0) 74.3 (9.3) 77.0(1.7) 74.3(4.4) 74.4(7.7) rliiwni ia ike % fat hi a 77.20.7) 73.4 (10.0) 73.9(10.1) 77.9 0.4) 79.0 5.0) 79.7 0.0) 79.7 (9.7) 79.7 (9.J) 04.9 (14.0) 47.9 04.0) 44.40.4). 44.4(3.3) 44.7 (4.01 44.0(4.3) 44.3 0-7) 43.3(3.7) 44.3 0.0) 94.0(4.0) 74.0 (10.9) 73.4(11.3) 43.7 (9.4) 43.7(4.9) 42 9(3.9) 33.0 0-3) 43 0 5.7) 0.7 0.7) 41.7 (4.3) 41.7 0.0) 42.3(4.7) 32.7(4.7) 42.3 0.0) HONS 0977S9 VoL 84