ySTTBlSCHOFP s $19 Santa Fe Avenue Albany, California AND 211 STATE OF CALIFORNIA DEPARTMENT OF NATURAL RESOURCES DIVISION OF FISH AND GAME SAN FRANCISCO, CALIFORNIA EARL WARREN GOVERNOR KENNETH I. FULTON DIRECTOR OF NATURAL RESOURCES FISH AND GAME COMMISSION NATE MILNOR, President Los Angeles GERMAIN BULCKE, Commissioner San Francisco EDWIN L. CARTY, Commissioner Oxnard LEE F. PAYNE, Commissioner Los Angeles W. B. WILLIAMS, Commissioner Alturas GEORGE P. MILLER, Executive Secretary San Francisco BUREAU OF FISH CONSERVATION A. C. TAFT, Chief San Francisco A. E. Burghduff, Supervisor of Fish Hatcheries San Francisco Brian Curtis, Supervising Fisheries Biologist San Francisco L. Phillips, Assistant Supervisor of Fish Hatcheries San Francisco George McCloud, Assistant Supervisor of Fish Hatcheries Mt. Shasta D. A. Clanton, Assistant Supervisor of Fish Hatcheries Fillmore Earl Leitritz, Assistant Supervisor of Fish Hatcheries San Francisco Allan Pollitt, Assistant Supervisor of Fish Hatcheries Tahoe William Berrian, Foreman, Fall Creek Hatchery Copco Archie Thompson, Foreman, Yosemite Hatchery Yosemlte John Marshall, Foreman, Feather River Hatchery Clio Leon Talbot, Foreman, Mt. Whitney Hatchery Independence A. N. Culver, In Charge, Kaweah Hatchery Three Rivers Donald Evins, Foreman, Lake Almanor Hatchery Westwood Ross McCloud, Foreman, Basin Creek Hatchery Tuolumne Peter Topp, Foreman, Burney Creek Hatchery Burney C. L. Frame, Foreman, Kings River Hatchery Fresno Harold Hewitt, Foreman, Prairie Creek Hatchery Orick Edward Clessen, Foreman, Brookdale Hatchery Brookdale Harry Cole, Foreman, Yuba River Hatchery Camptonville Clarence Chansler. Fish Hatchery Man, Madera Hatchery Bass Lake R. C. Lewis, Foreman, Hot Creek Hatchery Bishop Cecil Ray, In Charge, Kern Hatchery Kernville Carl Freyschlag, Foreman, Central Valley Hatchery Elk Grove Lloyd Shebley, In Charge, Mt. Tallac Hatchery Camp Richardson Joseph Wales, Biological Surveyor Mt. Shasta Leo Shapovalov, Senior Fisheries Biologist Stanford University William Dill, Senior Fisheries Biologist Fresno Chester Woodhull, Junior Aquatic Biologist Fresno BUREAU OF GAME CONSERVATION J. S. HUNTER, Chief San Francisco Gordon H. True, Jr., In Charge, Pittn.an-Robertson Projects San Francisco Donald D. McLean, Economic Biologist San Francisco Roy M. Wattenbarger, Supervisor Los Banos Refuge Los Banos Russell M. Reedy, Supervisor Imperial Refuge Calipatria Ralph R. Noble, Supervisor Suisun Refuge Joice Island Joe Vlasnik, Jr., Supervisor Elk Refuge Tupman John R. Wallace, In Charge, Predatory Animal Control San Francisco Asa L. Brown, Supervising Trapper Beaumont John L. McDonald, Supervising Trapper Anderson O. R. Shaw, Supervising Trapper Salinas BUREAU OF GAME FARMS AUGUST BADE, Chief Yountville E. D. Piatt, Superintendent, Los Serranos Game Farm Chino BUREAU OF MARINE FISHERIES RICHARD VAN CLEVE, Chief San Francisco S. H. Dado, Assistant Chief San Francisco W. L. Scofield, Supervising Fisheries Researcher Terminal Island G. H. Clark, Supervising Fisheries Researcher Stanford University Frances N. Clark, Supervising Fisheries Researcher Terminal Island Harry C. Godsil, Senior Fisheries Researcher San Diego Donald H. Fry, Jr., Senior Fisheries Researcher Terminal Island J. B. Phillips, Senior Fisheries Researcher Pacific Grove Paul Bonnot, Senior Fisheries Researcher Stanford University Geraldine Conner, Fisheries Statistician Terminal Island California Fish and Game "conservation of wild life through education." Volume 29 SAN FRANCISCO, JANUARY, 1943 No. 1 TABLE OF CONTENTS Page In the Service of Their Country 2 A Study of Nesting Canada Geese in Honey Lake Valley, Cali- fornia Jay S. Dow 3 Twelfth Annual Black Brant Census in California. -James Moffitt 19 The Effect of Mining Silt on Yield of Fry from Salmon Spawning Beds Paul A. Shaw and John A. Maga 29 Editorials and Notes — Special Regulations Affecting the 1942 Deer Season 42 Twenty -five Years Ago in "California Fish and Game" 43 Retirement of J. C. Lewis 44 Retirement of Henry Lencioni 44 Retirement of J. D. Dondero 45 Reports 46 California Fish and Game is a publication devoted to the conservation of wild- life. It is published quarterly by the California Division of Fish and Game. All material for publication should be sent to Brian Curtis, Editor, Division of Fish and Game, Ferry Building'. San Francisco, California. The articles published herein are not copyrighted and may be reproduced in other periodicals, provided due credit is given the author and the California Division of Fish and Game. Editors of newspapers and periodicals are invited to make use of pertinent material. Subscribers are requested to notify the Division of Fish and Game, Ferry Build- ing, San Francisco. California, of changes of address, giving old address as well as the new. 18211 ito HThe ^ertrice of i:htir (Tountrg Now serving with the armed forces of the United States are the following 99 employees of the California Division of Fish and Game, listed in order of entry into the service: J. William Cook Merton N. Rosen Albert King E. L. Macaulay Marvin Hagle Donald DeSpain E. R. Hyde George Werden, Jr. Arthur Boeke E. A. Johnson Henry Bartol Edson J. Smith John F. Janssen, Jr. Richard Kramer Arthur Barsuglia George Metcalf James F. Ashley William Jolley Rudolph Svvitzer Jacob Myers Charles McFall Lloyd Hume John E. Fitch William H.Sholes Jr. James Reynolds Paul Gillogley Ralph Beck Charles Cuddigan James H. Berrian Edward Dolder John Woodard Bob Kins Ross Waggoner John Canning William Richardson William Plett John Finigan Trevenen Wright John A. Maga Elmer Doty William Dye A. F. Crocker Lester Golden Richard N. Hardin Henry Frahm Lawrence Rubke Virgil Swenson Harold Dave Howard McCully Austin Alford Belton Evans Willis Evans James I liller Robert Terwilliger Eugene Durney Charles W. Kanig Howard Shebley Donald Tappe Richard S. Croker J. G. McKerlie Robert Kaneen Elmer Lloyd Brown Douglas Dowell William Roysten Dean L. Bennett John Chattin C. L. Towers Carlisle Van Ornum Harry Peters Mark I lalderman John B. Buttler Charles Comerford NilesJ. Millen Carol M. Ferrell J. Alfred Aplin William LaMarr C. L. Savage James E. Wade Nathan Rogan I Ienry Shebley S. Ross Hatton Jack Wm. Cook Bolton Hall John J. Barry Chester Ramsc\ Elmer Aldrich Robert N. I la it Ralph Dale James D. Stokes George D. Seymour Glenn Whitesell W. E. Scrimscher A. E. Johnson Gustav E. Geibel Wm. Bradford Ernest E. McBain John Hurley Karl Lund Elden H. Vestal milled in line of Butu Byron Sylvester (2) A STUDY OF NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA1 By Jay S. Dow Bureau of Game Conservation Division of Fish and Game The Canada goose (Branta canadensis canadensis) commonly referred to as the "Honker" is the only species of wild goose that nests as far south as California. According to Moffitt it breeds commonly in northeastern Cali- fornia, the normal breeding range closely paralleling the summer range of the Rocky Mountain mule deer in California. It isJ£nown_to_breed throughout Modoc and Lassen counties, wherever conditions are favor- 0> (.AMI The writer is convinced that he located more than 90 per cent of the nests in the study area, and it is possible that he actually located close to 100 per cent of them. As each nest was discovered, its location was spotted on a map and complete data concerning it were recorded in field notebooks to be transferred later to a nesting record form (Fig. 3). Each nest, with a few exceptions to be noted later, was revisited at intervals of not more than six days until its fate was determined. u 43 ■a u o CD a u > o o a 9 O **- a 43 03 D CO 9 to 0) "3 O H 3 «*— CO CO 0) 3 02 3 DQ m o £ P ■0 9 a CD CD T3 C P Cause of failure | 3 a CO a CD 43 o >> o O a 9 03 5 o U 4a 03 u ffi oS T3 s 43 L. CD CO 0) Q S 00 % Additional remarks 1 IV A 3/17 4 V V 2 X G 3/25 7 V V 3 V D 3/25 7 V 1 egg infertile 4 V B 3/28 6 V V Eggs covered 9 never returned 5 VII B 4/ 6 2 V 6 VII F 4/ 6 2 V 7 VIII H 4/ 7 6 V V 8 II C 4/ 9 6 V . 1 dead embryo 9 IV G 4/ 9 V V 10 I D 4/ 9 6 V Hatching 5/3 11 IX A 4/ 9 3 V V 12 VIII E 4/10 6 V V High spring run-off 13 VIII E 4/11 4 V V Farm machinery 14 VI A 4/12 10 V Double nest 3 dead embryo 15 III A 4/12 5 V V Tules burned by- ranchers Fig. 3. Sample nesting record form. Nests in the study area were easily found. Often several incubating birds were visible from one point of vantage. The geese nest in early spring when the grass in the fiat, open meadows is so short that the nest mounds can often be seen from a distance of 100 yards or more. Also, a nest can nearly always be located by observing the solicitous males. The gander usually stands in the vicinity of the nest while the female is incubating and protests loudly at the observer's approach. Nesting Dates The nesting season was already well under way when the study began on March 16, 1939. Ne.sts with eggs were most numerous by the middle of April (Fig. 4). By May 10th. all breeding activities had NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA 7 ceased with the following exception. On March 27, 1939, a nest con- taining six eggs was found on top of a haystack. On April 20th, the Tn^uhatmg bird was disturbed by photographers and left the nest for approximately two hours during the heat of the day. The goose continued to incubate until June 22d, when the writer took the eggs for examination. They all contained well-developed embryos which were dead, probably as a result of their prolonged exposure to the sun on April 20th. To the writer's knowledge the goose had incubated for 87 days. 55 50 45 40 35 30 2 5 1 939 1940 1 1 1 I \ \ \ 1/ /l \ \ / 1 / 1 \ \ \ \ 1 / / \ \ \ \ \ \ / \ \ \ \ \ \ 1 / \ \ \ \ \ V 20 / / \ \ \ \ I 5 1 0 5 / / / / 1 \ \ \ \ / / / / / / / / / / // // f\ __---- fl MARCH 1-15 MARCH 15-31 APR IL 1-15 APRIL 15-30 MAY I- 15 Fig. 4. Occurrence of nests during the 1939 and 1940 seasons by bi-weekly periods. In 1940, the first nest was discovered on March 6th. As in 1939, k^\\\\ If? th_ marked the, approximate -peak.. of the nesting season. The nests were visited for the last time on May 10th. by which date all of the broods had left the nests. In 1939, 140 nests were located containing 713 eggs, or an average ^ nf fi pp. Pggs jiprjTP^ in addition, 29 nests were discovered after they hax^ been destroyed or after the broods had hatched. In 1940, 215 nests were found containing 1.099 eggs, or 5.10 eggs per nest, and, in addition, 29 nests were discovered after they had been destroyed or after the broods had hatched. The average clutch size for 127 success- 8 CALIFORNIA FISH AND GAME ful nests iii 1!)4() was somewhat higher with an average of 5.48 eggs per nest. The average incubation period for Canada QgfiSfl nesting in their natural habitat is 28 olajm* This corresponds closely with reports from E. D. Piatt at the State Game Farm at Chino, California, who has bred honkers in captivity for many years. The distances of the nests from each other usually depended upon the strength and fighting ability of the ganders. Several especially pugnacious ganders were successful in keeping other nesting geese more than 150 yards from their incubating mates, while other pairs of geese were found to be nesting within 10 to 12 feet of one another without the slightest indication of fighting. Nesting Sites The one characteristic that nearly every nest studied had in com- mon was elevation above the surrounding terrain. Elevated sites offer a clear view of the surroundings and afford protection from floods, Fig. 5. Pair of nesting geese on haystack. Photograph by Janus Mollitt. grazing live stock, and farm machinery. By increasing the field of vision these also afford the incubating geese some protection against predation. This supposition is borne out by the fact thai during the course of the study only one adult goose was found killed on the nest by a predator. Ninety per cent of the nests were either surrounded by water or jvere within thirty feet of n lake, ditch, or flooded meadow. Nests in .such locations were usually elevated well above the water level. Musk- rat houses, mats of tules in dense clumps, or mounds of tule stems built up by the gee.se aided in elevating the nests. NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA After the eggs have hatched, the goose usually broods her young in the nest for twelve to twenty-four hours. The young are then led to open water, usually a lake or one of the deep canals, where the family remains until the young are able to fly. Hartson Reservoir (Pig. 2) is one of the favorite rearing areas in Honey Lake Valley, and during the course of this study, the margins of Honey Lake itself were used extensively. In some cases broods of geese traveled as far as four or five miles over marshy areas or along water courses in order to reach these large bodies of water. Haystacks (Fig. 5), ca- nal banks (Fig. 6), muskrat houses, matted masses of tules (Fig. 7), and sand islands were among the pre- ferred nesting sites. The ex- tensive use of haystacks as nesting sites afforded the writer an opportunity to make the following unusual observations : On April 14, 1940, the writer noticed a wagon load of hay which was stuck in the mud and abandoned tem- porarily by the owner. A nest containing six eggs was found on the exact top of the load at a height of 12 feet from the ground. When the nest was revisited a few days later, a mallard was found to be nesting on the same wagon within three feet of the incubating goose. Both were successful in hatching broods. On March 18, 1940, a goose nest containing two eggs was found on the top of one end of a large hay- stack, more than 18 feet from the ground. Two or more wagon loads of hay were being taken from the opposite end of the stack each day. As the haystack decreased in size and the nest was endangered, the rancher considerately moved the nest and eggs to a safer position on the stack. By April 25th, the stack had dwindled to only a small pile and the nest was less than six feet from the ground. The farmer was obliged to move the nest to save the eggs from destruction each time he took hay from the stack. A last visit to the nest revealed that the goose hatched two goslings in spite of the fact that she had been dis- urbed each day during the incubation period. The incubation period, in this case, was approximately 33 days. Fig. 6. Goose nest on canal bank. Canal in foreground, irrigated meadow in back- ground. Photograph by James Moffitt. 2 — 18211 10 CALIFORNIA PISH A.ND GAM E Nest Material and Construction When a variety of nesl material is available the nests are usually well made, bui. when the site is in a locality thai is devoid of vegetation such as a canal bank or sand island, the tiesj is often little more than a depression seratelird in 1 h . ■ ground and lined with down from £he goose's breast (Fig. 8). In marshy areas where ronnd-stemmed tules (Scirpus acutus) and three-square tules (Scirpus paludosus) are abundant, geese frequently build nest mounds, often piling tide stems a.s high as three feet above the ground or water level before beginning the construction of the nest proper. Many of the tule stems used in the mounds or in nest construction are broken from growing stalks. In some cases, areas Fig. 7. Typical mass of round -stemmed tule (Scirpus acutus), a favored nesting site. Photograph by James Moffltt. surrounding nests were denuded of tule growth for distances of from three to 10 feet. When nests are built on haystacks, tule mats, muskrat houses, or nest mounds, they are carefully constructed. A neat oval-shaped depression is usually made. 12 to 14 inches long, 8 to 10 inches wide, and 5 to 8 inches deep. The actual construction of the nest usually continues during the laying period, frequenl additions being made until about the beginning of the period of incubation. It is not until this time that the nest is finally lined with down. When the female leaves the nest for the feeding grounds, she care- fully covers the eggs with down from the nest lining. The down is an effective insulator; nests that have been left voluntarily by the incubat- ing female on cool days have been found to contain warm eggs two hours after she had left the nest. On hot days the down also acts as an insulator against the heat of the sun. NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA 11 Flushing Distance Williams and Marshall (1937) report that average flushing dis- tance during the early part of the nesting season, in April, was roughly 50 feet, and that nearly a month later the distance was reduced to an average of approximately 32 feet. Although the writer did not keep a detailed record of flushing dis- tances, it is safe to say that the average flushing distances were con- siderably less than those reported above. In fact, during the incuba- tion period, it was possible for the observer to walk or ride to within five or six feet of many nests without flushing the goose. Fig. 8. Goose nest on island in Hartson Reservoir photographed after incubation started. The goose has been disturbed so has not had time to cover eggs before leaving. Photograph by James Moffitt. This difference in flushing distances is probably due to the fact that Honey Lake Valley is an agricultural area and the geese quickly become accustomed to the almost daily presence of human beings in the vicinity of their nests. Nesting Types Eight distinct cover types were used by nesting geese (Table 1), but there was considerable variation in the selection of sites within each type. A. Tule : This type includes round-stemmed tule thickets border- ing canals, sloughs, and lake shores, and clumps of round-stemmed tule located in the marsh or meadow types. In 1939, 43 or 25.4 per cent of the nests were found in this type, compared with 99 or 39.8 per cent in 1940, an increase of 14.2 per cent. In 1940, cooperating ranchers 12 CALIFORNIA FISH AND GAME left many patches of round-stemmed tule that ordinarily would have been burned. Thus, a greater amount of this cover tj'pe was available. TABLE I Cover Types Utilized by Canada Geese in 1939 and 1940 and Percentage Distribution of Nests 19S9 1940 Cover Type (169 nests) (249 nests) A. Tule 25.4 — 39.8 B. Marsh 30.8 6.8 C. Island 12.4 20.0 D. Haystack 2.4 5.6 E. Irrigated Meadow 10.1 8.4 F. Muskrat House 7.7 0.4 G. Canal Bank 11.2 16.1 H. Willow 0.0 2.0 B. Marsh : The areas designated as marsh were those areas that wrere flooded during the spring season, or, if water were available, remained flooded the year around. They were distinguished from Type E (Irrigated Meadow) by ranker plant growth and The fact that they were never mowed, but instead grazed by live stock during the dry season. [Types A (Tule) and F (Muskrat Houses) were located within this type and could be considered as subtypes of Type B.] In 1939, 52 nests or 30.8 per cent were found in this nesting type. In 1940, only 17 nests or 6.8 per cent were found here. This marked decrease was due to the unusual high water levels that prevailed during the 1940 nesting season, forcing the nesting geese to higher and drier elevations. C. Island: Only 30 acres of islands were included in the entire study area, a fraction of 1 per cent of the total acreage. The fact that 21 nests or 12.4 per cent were found in Type C in 1939, and 52 nests or 20.9 per cent in 1940, indicates that islands are preferred nesting sites. The increase in the use of this type in 1940 was probably due to the prevalence of high water in other nesting areas. Also, the higher water level resulted in there being more islands. D. Haystacks : Haystacks were used as nesting sites by four pairs of geese or 2.4 per cent in 1939, and by 14 pairs or 5.6 per cent in 1940. The use of haystacks as nesting sites is directly correlated with the amount of hay used for winter feeding of live stock. Most of the stacks that were still present during the nesting seasons of 1939 and 1940 were used by nesting geese. E. Flooded Meadows: This type is similar to Type B (Marsh) in that it is ordinarily flooded during the nesting season. On the flooded meadows, however, water is under control. They are drained during June and July so that grasses and sedges can be harvested. In this type there are levees, dams, and occasional plots of high ground which afford nesting sites for geese. Seventeen or 10.1 per cent of the nests were found in meadows in 1939 and 21 or 8.4 per cent in 1940. F. Muskrat Houses : Thirteen nests or 7.7 per cent were found on muskrat houses in 1939 and only 1 or 0.4 per cent in 1940. NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA 13 Muskrats are heavily trapped in this area and permanent water is scarce, so the number of muskrat houses is limited. All of the muskrat houses were found within Type B. G. Canal Banks : This type was used commonly in the study area. Nineteen nests or 11.2 per cent were found on canal banks in 1939, and 40 nests or 16.1 per cent in 1940. Although canal banks in the study area had little cover, they are evidently preferred because they afforded the desirable combination of elevation plus visibility. H. Willow : It was evident that the dense willow thickets that dot the Honey Lake Valley landscape are not preferred nesting sites. No nests were found in this type in 1939, but in April 1940, when high water decreased the use of some of the other types, 5 nests or 2 per cent of the total were found in willows. It is interesting to note that none of the nests located in this type Avere successful. Fate of Nests In the course of the study the fate of 418 nests was determined. Each nest was visited at intervals of not more than six days until its fate was determined. The findings are shown graphically in Fig. 9. The writer recognizes the fact that the presence of an observer in the field can, in itself, affect the rate of nesting success. His presence, for instance, can cause an increase in the percentage of desertions. The frequent flushing of birds from the nests and the trails left as a result of his visits can cause an increase in predation losses. It is felt, however, that in the case of this study, the writer's activi- ties had little effect on the total results. Persons other than the writer were present in the area daily. In fact, many nests were reported by ranchers who found them during the course of normal farming opera- tions. Consequently, the writer's presence added but little to the normal hazards associated with agricultural use. Successful Nests In 1939, 52.5 per cent of the nests were successful. In 1940, broods were successfully hatched from 60 per cent. Successful nests were recognized by their appearance after the eggs were hatched. In nearly all cases the shells of the hatched eggs were crushed, presumably by the parent during the period that elapsed between hatching and leaving the nest, Only bits of shell and the crumpled inner shell membranes remained. In a few cases nests were torn up by predators after the eggs had hatched out, but the character- istic remains of hatched eggs were still present to indicate success. Unsuccessful Nests Desertion : In 1939, 11 or 6.5 per cent of the nests were deserted, compared with 18 or 7.3 per cent in 1940. Of the 29 nests deserted during the two year period, 14 were abandoned for unknown causes. Nine nests were deserted as the result of .fighting among geese in areas where nests were placed close together. In several instances an observer watched ganders fighting over nesting 14 CAIilFOKXIA FISH AMI CAMI: sites, and in nine cases the desertions of aests were traced directly to this cause. Six desertions were directly traced to ukui's acj ivities. The dis- turbances of irrigators traveling the canal banks with their dogs were responsible for five, and one was descried when the writer flushed an incubating goose from her nest while two crows were circling overhead. Believing thai the nest mighl be destroyed by these birds, the writer carefully covered the eggs, but the goose never returned. z Ul o a. a o. 70 60 50 40 30 20 10 Fig. 9 NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA 15 Nest Destruction by Predators It is not always easy to place the responsibility for nest destruction upon one particular predator. Most kinds of predators do, however, leave characteristic signs that may be accurately interpreted by an experienced observer. The manner in which different predators rob nests and eat eggs is often characteristic. Tracks, droppings, hair, and feathers all constitute dependable evidence. ^ov^yjfi^ Coyotes_were responsible for more nest destruction than were all other predatorV^ombined. A total of 59 nests were destroyed by coyotes on the study area during the two seasons; 27 nests or 16 per cent in 1939, and 32 nests or 13.3 per cent in 1940. In 1940, one goose was killed on her nest by a coyote. Fig. 10. Goose nest destroyed by coyote in Honey Lake Valley. Note scattered egg remains and torn up nest lining. Photograph by James D. Stokes. The methods employed by coyotes are characteristic and conse- quently their work is readily identifiable. Eggs eaten by coyotes in all cases were found crushed to bits. Nests were alwTays completely destroyed, and the down lining was scattered in all directions (Fig. 10). In several instances eggs with typical large canine tooth holes in them were found 50 to 75 feet or more from destroyed nests. An extreme instance of co,yote predation is illustrated by the case of a coyote that wraded and swam 50 yards to a sand island, ate 12 eggs from twTo nests, then scratched sand over five more nests with eggs, causing the geese to desert. Of the nests destroyed by coyotes, 46.8 per cent were on islands, 31.3 per cent in meadow, 12.5 per cent in tule, and 9.4 per cent in marsh. 16 CALIFORNIA FISH AND GAME Skunk: Skunks are masters of the arl of egg eating and their work is easily identifiable. The skunk makes a hole in the egg large enough to admit its pointed nose, then licks out the contents. The eggs are either rolled a few feet from the nest before being eaten or are eaten in the nest. The lining of the nest is not torn to bits as it is in the case of a coyote, and Tracks are usually in evidence. A skunk will ordinarily eat only two or three eggs from one nest. In no case was there evidence that a skunk returned to a raided nest for a second meal. Skunks were responsible for the destruction of 12 ncsls or 7.1 per cent in 1939. and 4 nests or 1.6 per cent in 1940. Qrows : Crows destroyed 6 or 3.5 per cent of the nests in 1939, and 2~or .8 per cent in 1940. Crows ordinarily peck one or two holes in the shell of an egg and only remove a part of the contents. Bits of shell are generally found stuck to the surface of the egg. A number of eggs were eaten by crows after the eggs had been scattered and cracked by other predators, but these are not included in the above figures. Other Losses \^|±ejii. Many nests were flooded during periods of excessive spring run-otr\Also, the strong winds that sweep across Honey Lake and adjacent smaller bodies of water drove the waves high over the normal shore line, washing out nests that were located near to water margins. During 1939, there was no high water and losses traceable to flooding consequently were small, amounting to only 2 nests or 1.2 per cent. In 1940, high water occurring during the last few days of March destroyed 35 or 14.1 per cent of the nests under observation. Eire: Fire destroyed 10 nests or 5.9 per cent during the 1939 season. The ranchers in Honey Lake Valley attempt to control the growth of round-stemmed tule by winter and spring burning. All of the nests destroyed by fire in 1939 were located in tule masses. In 1940, the ranchers, who proved to be a very cooperative group, com- pleted the burning program before the beginning of the nesting season and no nests were destroyed. ('utile: T1h> number of ncsls destroyed as the resull of trampling by cattle was small ; 2 or 1.2 per cent in 1939, and 4 or 1.7 in 1940. Hundreds of cattle were grazed on the study area during the nesting season, but most of the nesting sites were located in areas that were not heavily grazed. Miscellaneous: Fifteen ncsls were destroyed during the two-year period by what the writer chooses to call miscellaneous causes. Ten or 6 per cent were so destroyed in 1939, and 5 or 2 per cent during 1940. Three nests listed as destroyed by farm machinery were broken up by drags used by the farmers to smooth out meadows. One was destroyed indirectly when a mink tore up a muskrat house on which the nest was placed. Another nest located on a muskrat house was destroyed when the rats worked up through the bottom of the nest, allowing the eggs to drop into the house cavity. As noted earlier in the paper, another nest was destroyed as the result of exposure to the sun. One goose was found dead on her nest. The Poultry Patho- logical Laboratory of the University of California determined the NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA 17 cause of death to be aspergillosis, a fungus infection of the respiratory tract. The cause of eight unsuccessful nestings was undetermined. Egg Fertility During the 1940 season, a record of egg fertility was kept on 127 successful nests. These nests contained a total of 697 eggs or an average of 5.48 eggs per nest. Six hundred and forty-nine or 93 per cent of the eggs produced goslings. Williams and Marshall (1937) reported an average clutch of 4.8 eggs and a hatch of 81 per cent for a total of 84 nests and 410 eggs. Of the 48 eggs that did not hatch, 16 or 33.3 per cent were infertile. In 17 or 35.3 per cent there were partially developed embryos, and in 15 or 31.4 per cent of the eggs the goslings were well developed but had died before hatching. In each of the latter cases, the yolk sac was still unabsorbed. Three unhatched eggs were found in each of three successful nests. These eggs all contained dead, partly-developed embryos. No doubt these eggs were deposited by another female goose after incubation of the original clutch had started, and the extra eggs were abandoned after the original clutch had hatched. With the exception of the three cases noted above, all of the other unhatched eggs were found singly. Management It is possible that through the application of management methods the number of geese produced annually in Honey Lake Valley may be increased. The control of predators, particularly coyotes, in the prenesting season will prove to be an effective management tool. Some coyote control work is being carried on in the valley at the present time, but it is not intensive enough to give the required amount of protection to the geese during the nesting season. Where it is practicable and compatible with the other interests of an agricultural community, the more efficient control of water levels will result in the elimination of losses due to the flooding of nesting sites. The writer has already mentioned that losses due to fire were prevented in 1940 by inducing ranchers to complete tule burning opera- tions prior to the nesting season. The continuance of this practice should be encouraged. In view of the cooperative attitude of the ranchers, it may also be possible to eliminate losses caused by drags used to level meadow land during the spring months and by ditch and levee cleaning operations. It is important that tule masses, which are favored nesting sites, be left unburned where their presence will not interfere with farming operations. Additional nesting sites may be provided by the construc- tion of islands in Hartson Reservoir and along the margins of Honey Lake. 3—18211 IS CALIFORNIA PISH AND GAME Summary 1. A study was made of nesting Canada Geese on a 15,560 acre area in Honey Cake Valley, California, in 1939 and 1940. Case his- tories were obtained on 160 nests in 1939 and -V.) in 1940. 2. During both years the nesting season began about March 1st. reached >'s peak by April 15th and ended by May 10th. 3. In l!):i!», 140 nests contained 713 eggs; an average clutch of 5.09. In 1940, 215 nests contained 1,099 eggs; an average of ~>.in. The average incubation period was 28 days. 4. Elevation above surrounding terrain seemed to be the most important characteristic of nesting sites. Proximity to water was another important requisite, 90 per ceul of the nests being either surrounded by or not more than 30 feet from water. 5. Eight distinct cover types used by nesting geese were recog- nized. These were tide, marsh, island, haystack, irrigated meadow, muskrat house, canal bank, and willow. Tide, marsh, island, and canal bank were the preferred types. 6. The fate of 418 nests was determined. Tn 1939, 52.5 per cent and in 1940, 60 per cent of the nests were successful. Predation was responsible for the failure of the majority of unsuccessful nests. Flood, fire, trampling by cattle, and other miscellaneous factors also caused the destruction of nests. 7. During 1940, a record of e^ CALIFORNIA FISH AND GAME the lagoon. At the time of the L942 census, however, eelgrass was observed by Bedwell to be growing up through the silt, so thai normal conditions may be reestablished, provided thai further Large deposits of silt do not occur. Bedwell further advised thai a1 no time were eelgrass stands a1 the extreme south end of the bay affected by the silt and thai at the time of the census, there was sufficient eelgrass for the small num- ber of birds found present. Samples of eelgrass collected by Bedwell on February 16, 19-12, for Dr. Etenn, were found by the latter not to be affected by Labyrinthula. Warden Glidden made observations of eelgrass conditions and col- lected samples in Mission Bay on February 10, 1942, and again in mid- March. He reported that the plant was plentiful in this bay where larger growths of apparently healthy eelgrass were found than in pre- vious years. Samples were taken from two localities in .Mission Bay and examined by Dr. Renn who found Labyrinthula positively present in one of them and not in the other. Since Labyrinthula was also found in samples collected by Glidden in 1941, the disease has appar- ently been present locally for at least several months with little or no visible deleterious effect upon the plant's abundance. It will be inter- esting to watch the future developments in this area to see if the disease has so recently reached the locality as not yet to have caused depletion, or whether some other factor is responsible, such as specialized local conditions, or a less susceptible strain of eelgrass along the southern part of the Pacific Coast. In the spring of 10-12. as in 1941, Glidden was unable to find any eelgrass in San Diego Bay where the plant appears to have been com- pletely killed out by some cause. In spite of this fact, the largest number of brant reported in any of the 12 annual censuses was recorded in 1942. In reporting this fact, Glidden commented thai he wondered upon what the brant of San Diego Bay subsisted, lie stated that this population and that of Mission Bay do not appear to exchange posi- tions and that the birds of San Diego Bay seem to remain there for a considerable time. The writer believes that the brant of San Diego Bay may subsist to a large extent upon sea lettuce (Ulr41. The eggs were fertilized in the usual manner and covered with water in a 10-gallon fish planting can where they were allowed to harden for one hour before transpor- tation to the hatchery. Distribution of Eggs The eggs were thoroughly mixed so that each experimental group would be uniform in character. Groups of 500 eggs were then counted and placed on the gravel in each of the 21 nests. The eggs were then covered by three to four inches of similar gravel and the trough drains arranged to maintain one to two inches of water above this level. In a EFFECT OF MINING SILT ON YIELD OF PET PROM SALMON BEDS 31 fourth trough 13,600 additional eggs were placed in each of two standard hatching baskets for determining the time of hatch and yield of fry under the usual hatchery procedure. Addition of Mining Silt The seven nests of Trough 1 received only the hatchery supply of water without addition of mining silt and served as a control for determining the yield of fry from salmon eggs in unsilted gravel beds, and also provided a comparison with the normal basket hatch. For producing turbidity in the 14 nests of Troughs 2 and 3, wet mining silt was secured from the settling ponds of the Pacific Placers Engineering Company on Arkansas Creek, a tributary of the Cosumnes River. This material was typical of the fine silt and slimes discharged by gold dredging operations in many California mining areas. Figure 12 is a photograph showing the crew collecting this material. Fig. 12. Crew collecting mining silt for experiment. Two to three buckets of the wet slimes were agitated in a barrel of water by means of a recirculating pump and the addition of a small stream of water from the hatchery supply produced a muddy overflow which was led to the desired point of application by a small wooden flume installed between experimental Troughs 2 and 3. Fed in the manner described, the above quantity of silt lasted 2 to 4 hours after which the experimental nests received only hatchery water until the following day. The silt laden water from the flume was introduced at the desired nest by boring f" holes in the side of the flume. Outlets not in use were plugged with rubber stoppers. The muddy water was always added between nests and above the baffle board in order to cause mixing with the hatchery water before reaching the adjacent gravel nest. In Trough 2 the turbid water was started above the first nest on January 7th, the initial day of the experiment. Entering at this point, 32 CALIFORNIA PISH AND GAME the flow of water carried silt to all seven nests of the trough. During the course of the experiment the point of silt application was changed to gravel nests further downstream, thus producing turbidity in the lower nests for progressively longer periods, while the upper nests received silt onty for the earlier stages of the incubation period. The above procedure was reversed for Trough 3 in which silt was first applied to nest 7 and was progressively changed to upstream points as the period of incubation advanced. Silting was discontinued on March 20th. Thus the upper three nests did not receive silt during incubation but were subjected to silt for varying portions of the early emergence period. The' four lower nests received silt during the first half of the emergence period and also were silted for progressively longer portions of the incubation period, nest 7 receiving silt from the initial day of the experiment. The period of silt addition for Troughs 2 and 3 may be visualized by referring to Figures 15 or 17. Analyses and Records Records were kept of water temperature, volume of flow, dissolved oxygen, pH, and suspended solids. Analyses will be found in Tables 4 and 5. In summary, the water temperature varied from 48° to 54° F. ; dissolved oxygen from 10.0 to 11.8 p. p.m., and pH from 7.4 to 7.6. No appreciable difference in oxygon content was found above and below the gravel nests. The water flow in the trough containing the basket hatch was maintained at approximately 18 gallons per minute, while the flow in the three gravel bed troughs was approximately 8 gallons per minute. Seven analyses of the suspended solids content of overflow water below the lowest nests of Troughs 2 and 3 showed an average of 1176 p.p.m. (Table 5). At the same time values for points 1-3 nests upstream showed an average of 1330 p.p.m. The average loss per nest was 83 p.p.m. While this may appear to be a high rate of deposi- tion it should be remembered that silting was limited to 2-4 hours daily and that a gradual decrease occurred during this period from the above amount to clear hatchery water. As fry began to appear above the gravel they were collected, counted and preserved with formaldehyde in bottles numbered to correspond to the different nests. After one hundred days, when no further fry appeared, the gravel was carefully removed from each nest in order to count and observe the condition of eggs and fry that remained in the beds. Experimental Results Yield of Fry— Basket Control The salmon eggs that were handled by baskets in flowing water according to usual hatchery procedure hatched between February 12 and 14, corresponding to an incubation period of 36-38 days. The yield was 79.9%. The temperature averaged 51.3° F. for the 38 days to maximum hatch from which it may be calculated that 733 tempera- ture units were required. EFFECT OF MINING SILT ON YIELD OF FRY FROM SALMON BEDS 33 Yield of Fry — Gravel Control Nests The first fry appeared above the gravel in six of the control nests of Trough 1 on February 27th. Assuming that the hatch time in the gravel corresponded to the basket hatch, then 13 days elapsed to first emergence of fry above the gravel. The temperature during this period averaged 51.9° F., representing an additional 259 temperature units. In the other nest (#3) the first fry appeared on March 4. Fry emerged for 44 days, until April 11, or a total of 94 days from the start of the experiment. The seven control nests yielded an average of 16.2% and a maximum of 25.4% fry from eggs (see Table 1). At the conclusion of the experiment the entire mass of gravel from each control bed was searched and the remaining eggs and fry counted. (See Table 1.) TABLE I Yield and Recoveries from Gravel Control Nests (500 Salmon Eggs per Nest) Yield of Fry Fry and Eggs Recovered from Gravel Nest Number of Fry Per Cent Yield Number of Fry Number of Egss 1 2 3 4 5 6 7 30 8 64 127 106 111 120 6.0 1.6 12.8 25.4 21.2 22.2 24.0 36 3 5 24 12 7 35 4 4 9 1 11 14 3 Total 566 122 46 Average 81 16.2 17 7 During the incubation period several storms brought in natural sediment which tended to settle in the upper nests of the trough. Samples taken during one storm contained 50 p. p.m. of suspended solids above nest 1 and 33 p.p.m. below nest 7, indicating a deposition of 17 p.p.m. Visual observation indicated that most of this sediment, which was very dark in color, settled on the first three nests while the last four were relatively free from silt. The higher and fairly constant yield of live fry from the last four nests is therefore repre- sentative of development without appreciable silting, while the lower values from nests 1-3 represent yield of fry for gravel beds that were subject to natural silting. Previous experiments by Shapovalov (1937) on development of steelhead eggs in artificial gravel nests resulted in a yield of 29.8% during a period of storms and a yield of 79.9% in tests at a later date when storms were not prevalent. Further experi- ments by the same author (Shapovalov and Berrian, 1939) on develop- ment of salmon eggs in gravel resulted in the low yield of 10.2% which was attributed to silting from severe storms. ::i CALIFORNIA PISH AND OAME The rate of appearance above the gravel is of considerable inter- est and i.s shown in Figure L3 as the total oumber of fry for all seven control nests with respect to the time of emergence. The peak emergence, as shown by the slope of the curve, occurred 20-22 days alter appearance of the firsl Pry. The rate then decreased until the last fish appeared on the forty-fourth day. Table (i includes the date and number of fish appearing from all control nests. a* TOTAL YIELD OF EMERGING FRY _l 600 500 HRAVFI mMTRDI K / < 400 >- O. U. _J i/v-i TOTA o i a; 100 ID Id 10 15 20 25 30 EMERGENCE PERIOD - DAYS Fig. 13 35 40 45 In no case was the recovery of live fry plus fry and eggs in the gravel greater than 158 out of 500 originally placed in each nest. The recovery of relatively few eggs therefore indicates that undeveloped ones had decomposed and disappeared, as would be expected. The number of fry that hatched but died without working up through the gravel was relatively small. Yield of Fry— Early Silt Addition Table 2 shows the essential data for the seven nests of Trough 2 which received mining silt for varying time periods from the beginning of the experiment. The yield of Try from nest 7 is not included since this nest was dug into and the deposited silt flushed off on March 9th, when it was though! no fry were going to emerge from this series. The average yield of 1.1RI5 _*_ BED NO 1 SERIES III. FRY THAT WORKED THROUGH GRAVEL BEDS JAN .1. BASKET HATCH PERIOD 7 FEB I? FEB.27. M«?3Q APR.15. \ ' .. | TIME.OF 1ST FISH THR0UGta6RAVEL\ \ i i 1 il J TOTAL PERIOD THROUGH GRAVEL-^ o t a — o < — b in BED NO 1 Fig. 16. A composite photograph showing the fry that emerged from the 7 control nests and the 14 silted nests in relation to the silting period. As explained in the text, Nest 7, Series II and Nest I, Series III, should be disregarded. EFFECT OF MINING SILT ON YIELD OF FRY FROM SALMON BEDS 39 earlier silt additions extending back into the incubation period pro dueed progressively lower yields which reached beginning of the incubation period. In this undeveloped eggs thai were coated and preset steadily with earlier and longer periods of si fish that hatched failed to emerge but many forward through a screen rather than upward deposited silt. zero with silting at the series the number of ved with silt increased It addition. Very few fry apparently worked through the gravel and