2nd Brood Research Articles

Integration of molecular with higher-level effects of dietary zinc exposure in Daphnia magna

We exposed Daphnia magna for 21 days to dietary Zn, incorporated in a diet of the green alga Pseudokirchneriella subcapitata at 720 µg Zn/g dry wt and compared its response to D. magna fed with a control diet (116 µg Zn/g dry wt). Exposure to dietary Zn resulted in an increased body burden of D. magna (93.7 µg/g dry wt vs. 61.3 µg/g dry wt in the control) but did not affect survival, growth, or feeding rate. Only reproduction was significantly reduced from the 2nd brood onwards. Gene expression analysis, using microarray analysis and RT-PCR, showed that dietary Zn exposure resulted in the differential expression of several genes involved in molting-associated processes (i.e., chitin binding, cuticle metabolism), especially after 6 days of exposures (but not after 13 or 21 days of exposure). Monitoring of time to molt and intermolt-period confirmed this molting effect at the organism level in the first week of exposure. The data suggest a possible link between Zn-induced effects on molting-related processes and reproductive inhibition, but this link is only obvious for effects on the 2nd brood size and not for later broods. Reproductive inhibition in later broods may also be explained by a disturbed mitochondrial function, but more research is clearly needed to give a more definitive integrated explanation of the observed effects at the molecular and organism level.

Life Cycle and Social Behavior in a Heathland Population of Exoneura robusta (Hymenoptera: Apidae): Habitat Influences Opportunities for Sib Rearing in a Primitively Social Bee

Montane populations of the allodapine bee Exoneura robusta Cockerell in southern Victoria, Australia, have been the subject of numerous studies of sociality over the last decade. These populations are univoltine and colonies exhibit a semisocial/quasisocial polymorphism. Synchronous brood development and restricted periods of egg laying in these populations severely limit opportunities for sib rearing by older daughters. Here, we report the life cycle and social behavior of a conspecific subcoastal heathland population from southern Victoria. Colony sizes and intracolony relatedness are lower in the heathland population, possibly because the nesting substrate is relatively short-lived and spatially dispersed. Brood development is relatively rapid at the heathland locality, such that some colonies are able to produce a 2nd brood in late summer. As a result, opportunities for sib rearing frequently occur in heathland E. robusta, allowing for quite different forms of alloparental care than occurs in montane populations. The presence of opportunities for sib-rearing behavior in this species provides evidence of habitat mediation of sociality that is not caused by latitudinal variation.

Apple, Evaluation of Bacillus Thuringiensis Products for Tabm, 1995

Abstract Two rates of two Bacillus thuringiensis products were compared to the organophosphate Lorsban for control of TABM. The treatments were applied to single tree plots in a randomized complete block design consisting of 3 replicates of ‘Golden Delicious’ and 3 replicates of ‘Rome Beauty’. Treated plots were separated by others not sprayed with insecticides. The trees were 17 yr old and planted at a spacing of 24 X 35 ft. Sprays were applied with a handgun at 400 psi from a truck-mounted sprayer equipped with a Kohler 23 gpm pump. Approximately 5.5 gal of spray were applied per replicate tree (ca 300 gpa). The dates of application for the treatments were 9 and 23 Jun (1st brood control, 20-30% and 80-90% egg hatch [585-640 degree days (DD) and 910-965 DD, respectively, from first phenomena trap capture of TABM) and 11, 21 and 31 Aug (2nd brood control, 20-30%, 50-60% and 80-90% egg hatch [2355-2435 DD, 2585-2665 DD and 2815-2890 DD, respectively, from first trap capture of TABM). All plots received a regular fungicide maintenance schedule of Benlate 50DF, Dithane 75DF, Nova 40WP and Ziram 76WP. Also, an alternate row middle application of Swat 8EC was made for aphid control on 29 Jun and an alternate row middle application of Kelthane 50WP plus Carzol 92SP was made for mite suppression on 28 Jul. Effect of the test chemicals on the ERM/TSSM complex was evaluated by counting the mites several times during the season on samples of 25 random leaves/tree, 150 leaves/ treatment. Shelters of the various leafrollers were counted in a 5 min examination of each replicate on 18 Jul. All larvae were collected and returned to the laboratory for identification. On 20 Sep, ≈ 150 apples (75 top and 75 bottom) were randomly sampled for fruit injury from each ‘Golden Delicious’ tree. On 2 Oct the same number of apples and sampling scheme was used for each ‘Rome Beauty’ tree. Up to 25 dropped fruit per tree were also evaluated for fruit injury.

Apple, Effects of Various BT Products on Leafroller Management, 1994

Abstract Experimental sprays were applied to single-tree plots in a completely randomized design consisting of 3 replicates of ‘Delicious’ and 3 replicates of ‘Stayman’. Treated plots were separated by others not sprayed with insecticides. The trees were 16 years old and planted at a spacing of 12 × 35 ft. Sprays were applied with a handgun from a John Bean sprayer, 35 gpm pump. Approximately 3.5 gallons of spray were applied per replicate tree (ca 360 gpa). The dates of application for the treatments were 13 and 21 Jun (1st brood control) and 8, 19 and 31 Aug (2nd brood control). All plots received a regular fungicide maintenance schedule of Benlate 50DF, Dithane 75DF, Nova 40WP and Ziram 76WP. Effectiveness on SA was evaluated by counting the number of aphid-infested leaves/10 side terminals, and the number of aphids/most infested leaf where a rating scale (0-3) was used (see table footnotes for scale). The number of aphid natural enemies was determined by counting the number observed on 10 terminals per tree. Effectiveness of the test chemicals on the ERM and ZM was evaluated by counting the mites several times during the season on samples of 25 random leaves/tree, 150 leaves/treatment. Shelters of the various leafrollers were counted in a 5 min examination of each plot tree. All larvae were collected and returned to the laboratory for identification. STLM was evaluated by a 5-min count of mines around the periphery of the trees. A harvest fruit rating was made on 23 Sept.

Relation between First and Second Brood Production in the Bark Beetle Ips Typographus (Scolytidae)

Results suggest that a single female is equally good at producing a 2nd brood as a pair, and that female density during the 1st oviposition period does not influence the size of the 2nd brood. Female residence time with the 1st brood, body size, weight and lipid content explained little of the large variation in 2nd brood size. -from Authors

How Do Great Tit (Parus Major) Pair Mates Cooperate in Brood Defence?

Using economic theory CHASE (1980) predicted that a member of a group should contribute to the group's common interest, i. e. cooperate, as a function of the other members' contributions. In a group of two, e.g., a pair of parents caring for offspring, there are three possible stable equilibria of genuine cooperation: 1) Solely the male invests; 2) Solely the female invests; 3) Male and female invest into their common interest. It was examined in which of these ways members of great tit (Parus major) pairs cooperate while defending their nestlings and themselves against predatory danger of two sorts (owl (Glaucidium perlatum) + mixed mobbing chorus; the latter only). Employing multiway contingency analysis and information theoretic analysis it was also examined whether pair mates coordinate their defence among themselves. The experiments comprised of 1st and 2nd broods over five seasons in Lower Saxon wood plots. The following results were found: 1. Pair mates cooperate by confronting the danger jointly in 77.2 % of all cases tested (n = 158 pairs). In pairs with only one mate cooperating it is more often the male (15.2%) than the female (3.2%) that contributes to defence. In only 4.4% of all pairs both pair mates display noncooperative behaviour. There is no difference among broods of a season and the stimuli employed. 2. During a defence episode, mates of 1st brood pairs repeatedly approach the owl in succession jointly and withdraw from it likewise rather than alternate direction among each other's successive moves. The spatio-temporal dynamics implied in this synergism cannot be due to pair-specific environmental commonalities (brood, nest environs, etc.) at the time of the test, as is possible for the gross cooperation mentioned (1.); rather pair mates appear to gear their risk-taking to one another. From 5 to 29% of the variance of all moves' directions is thus explained by an influence of the mate's move. Another significant influence lies in a bird's own moves in that, on average, homing in on the danger and retreating from it, tend to alternate. The diminution of synergism between broods in both mates may be due to their becoming more familiar with their nest environs, as indicated both by comparison within the 1st brood and by a sexual difference in the strength of synergism. 3. In moving synergistically (see 2.), the male exerts a stronger facilitatory influence on the female than vice versa. This sex-specific effect abates between broods. The facilitatory effect on the mate tends to disappear after 15 to 30 s, i. e. tends to affect but the mate's next move in time. 4. Coordination of defence is also borne out by both mates homing in on the predatory danger more closely once both are present, as measured by their within-trial average distance from danger. This suggests for the first time that, apart from the accepted determinants of altruism, that the degree of altruism exhibited by a group member feeds back positively on that of another. A short term self-protection hypothesis for this type of synergism is rejected. Like the synergism of moving jointly (2.), this type of synergism is due to mutual positive feedback among the pair mates. 5. Between 1st and 2nd broods, the female's within-trial average distance from danger tends to relax both in the presence and in the absence of the male whereas the male's does not. This sex difference may be due to the male's greater interest in the pair's home range. Pestering a raptor with perseverence at an average distance tends to move it on. By contrast, the 2nd brood male's riskier, yet shorter-term minimum distance in the female's presence has relaxed, thus supporting a female-investment explanation for this measure.

The Defence of First and Second Broods by Great Tit (Parus major) Parents: A Test of Predictive Sociobiology1

Abstract and SummaryWe examined the extent to which parental investment, as measured by brood defence, is determined by selection via life history in a short‐lived bird, the great tit (Parus major). Great tit parents tending 1st and 2nd broods of the season were used to test five predictions of a cost/benefit model of brood defence based on the species average demography. The benefit was envisaged as the brood's contribution to a parent's fitness, and the cost as the potential loss if the defender dies in the act of defence; this loss was mirrored by Residual Reproductive Value plus a fraction of the brood dying as a consequence of the defender's death. Univariate and multivariate procedures were applied to six measures of defence response in 221 experimentally naive great tit pairs with nestlings. Stimuli consisted of a live raptor and a multi‐species taped mobbing chorus (both of which triggered strong alarm), the latter alone, and a novel, visual stimulus inhibiting nest visits for some time. As predicted by the model, response strength and associated risk increased with (1) advancing time in the breeding season, (2) the age of young, and (3) the number of young in 2nd broods. The last finding, being non‐trivial, is the strongest and the only unequivocal support for the notion that life‐history has moulded parental investment also in a short‐lived species; findings (1) and (2) could be alternatively accounted for by simply assuming that parents tailor their defence to environmental conditions permitting a new breeding episode. The model failed to predict the change of defence behaviour between 1st and 2nd broods. Instead, proximate factors coupled to the precise breeding area proved to be of prime importance in determining defence level, thereby falsifying the idea of a rigidly preprogrammed change of response level based on population parameter means. Instead, parents might gauge their defence to quality of young, as also allowed for in the model, or they may sometimes be constrained to display the full defence.As a by‐product, the experiments permit us to narrow down the range of selective agents producing the male parent's stronger defence. The sex difference, being prevalent in 1st broods and abating in 2nd broods, indicates that the male, by its defence behaviour, not only invests in its offspring but also in its home range and/or its mate. The latter interpretation is supported most directly by the male's defence behaviour in 1st broods.

Second Broods in Wood Ducks

Of 1,626 nesting attempts by wood ducks (Aix sponsa) in southeastern Missouri, 35 were 2nd clutches that were laid in the same season after an initial nest was successful. Most 2nd nests were initiated between 15 and 30 May and were an average of 876 m away from 1st nests. Clutch sizes were different between 1st and 2nd clutches, but hatching success was not. Most females known to raise 2nd broods were 2 years of age or older. Females with 2nd nests weighed less at initiation of incubation and lost less weight per day than during the 1st nesting. J. WILDL. MANAGE. 47(2):320-326 Wild anatids are not normally doublebrooded (Weller 1964:60), but some wood ducks are known to have more than 1 successful nest in a season. Thirty-nine cases of 2nd broods in box-nesting wood ducks have been reported in the literature (Table 1). This paper reports 2nd broods of wood ducks in southeastern Missouri. We present information on frequency of occurrence, distance moved, interval between the 2 nesting attempts, and the ages and weights of females that produced 2nd broods. We also examined the potential impact of 2nd broods on production of wood ducks. All records are from females nesting in boxes in southeastern Missouri within the 11,175-ha Mingo Swamp on Mingo National Wildlife Refuge (NWR) and Duck Creek Wildlife Management Area (WMA). This lowland hardwood wetland is the largest remnant of wood duck breeding habitat in Missouri (Korte and Fredrickson 1977, Fredrickson 1980). We are indebted to many colleagues for assistance and encouragement throughout the study. F. E. Hester, D. S. Gilmer, and T. S. Baskett reviewed the manuscript. G. W. Hartman, R. L. Clawson, C. E. Korschgen, R. E. Dobbins, N. R. Holler, M. J. Huebschen, and J. P. Rogers assisted with box checks. J. L. Boyles and B. T. Crawford of the Missouri Department of Conservation and J. E. Toll of the U.S. Fish and Wildlife Service made equipment and supplies available for our use.

European Corn Borer 2nd Brood Control, 1982

Abstract Six insecticide treatments were examined to determine their effects on second brood European corn borer larvae infesting field corn. Two applications of each product were made on 21 Jul and 4 Aug, after first generation moths became abundant in the blacklight trap next to the field. A randomized block design was used with 4 replications in ‘Pioneer 3184’ corn grown on the Vernon Delano Farm in Richmond Co, VA. Individual plots were 3 rows 25 ft long and spaced 3 ft apart. Each spray concentrate was directed towards the forming ear with a CO2-powered sprayer at 32 psi that delivered 29 gal of finished formulation per acre. Individual plots were evaluated at harvest 13 Sep, by recording % stalks bored, % stalks lodged, % ear shanks bored and yield in 25 row-ft.

European Corn Borer 2nd Brood Control, 1981

Abstract Four insecticides were examined to determine their effects on second brood European corn borer larvae infesting corn. Insecticides were applied Jul 21, when first generation moths became abundant in the blacklight trap next to the field. A completely randomized design was used with 4 replications in ‘Pioneer 3780’ corn grown on the Harold Delano Farm in Richmond Co., VA. Individual plots were 4 rows 25 ft long and spaced 3 ft apart. Each spray concentrate was directed towards the forming ear with a CO2-powered back-pack sprayer at 40 psi that delivered 20 gal of finished formulation per acre. Individual plots were evaluated at harvest on Sep 9, by recording % stalks lodged, % stalks bored, % ear shanks bored and yield.

Seasonal Abundance of Fleas (Siphonaptera) and Sucking Lice (Anoplura) on Gray Squirrels, Sciurus Carolinensis, in Central Tennessee, USA

Three species of lice and 1 species of flea occurred on Gray Squirrels, Sciurus carolinensis , in a deciduous woodland near Nashville, Davidson Co., Tennessee, USA. These were Hoplopleura sciuricola, Neohaematopinus sciuri, Enderleinellus longiceps and Orchopeas howardii. H. sciuricola increased in abundance over the last half of the year, whereas both N. sciuri and E. longiceps showed midsummer and midwinter peaks. An early spring peak in O. howardii abundance coincided with parturition and parental care of the 1st brood of young among the host population; female fleas were most prevalent at about this time as well as during the corresponding period for the 2nd brood of young. Male hosts were generally more heavily infested than females by all ectoparasites.

Cabbage Maggot Control on Transplanted Cabbage, 1979

Abstract Plots consisted of 250-ft rows bordered by 2 untreated rows on each side. Cabbages were transplanted Jul 10 in a Lima silt loam soil, replicated 4 times in a randomized complete block design. All insecticide applications were based on a 24 in row width. The directed sprays were applied at the bases of the plants in a 2 - 4 in wide spray band on Jul 12 using 2 flat fan nozzles (1510)/row delivering 171 GPA. The transplant treatment was by hand to ensure that the correct amount of the insecticide solution was applied in the proper location. After making a small hole with a hand trowel, 7 oz of the insecticide mixture were poured around the roots of the transplants and then the hole was filled. Foliar treatments timed for the adult fly peak of the 2nd brood of cabbage maggots were applied Aug 13 with a tractor-powered sprayer delivering 30 GPA through 3 flatfan nozzles (110015)/row. Damage assessments were made Sep 14 by pulling, washing and counting the number of cabbage maggot tunnels in 10 roots/treatment.

Influence of Age and Habitat on Reproduction by the American Goldfinch

During the summers of 1968—1975 the breeding biology of a color—marked population of goldfinches was studied in natural, nursery, and city habitats at Guelph, Ontario, Canada. Nesting began in early July, the mean date for the laying of the first egg laid each year varying by only 7 days and the mean date for the 1st clutches by 2.6 days. Old ♀ ♀ (birds in their 2nd breeding seasons or older) were mainly responsible for early nesting, and the percentage of such birds involved with breeding became less as the season progressed. The height of nesting occurred in the latter half of July, and no new nests were begun after August. The largest clutches (mean 5.3 eggs) were laid by old ♀ ♀, which in turn laid a higher percentage of 6—and—7—egg clutches than did presumed 1st—year birds. The age of the @M may also influence clutch—size since the largest recorded clutches (mean 5.6 eggs) belonged to old ♂ ♂ paired with old ♀ ♀. Habitat also affected clutch—size, the nursery having the highest (5.6 eggs) which was followed by the city (5.2 eggs) and finally by the natural habitat (5.0 eggs). The differences in clutch—size may have been influenced by the age structure of the breeding populations in each habitat, by differences in time of nesting and breeding population density, and by effects of cowbird parasitism. Clutch—size diminished with season, July clutches being significantly larger than August clutches. Nesting records suggest that 6.0 eggs forms the most productive clutch—size for the American Goldfinch. Old ♀ ♀ had a higher success, both in terms of numbers of young fledged/nest and ratio of successful nests, than presumed 1st—time nesters. Age of ♂ ♂ may also affect nesting success, as in matings between old ♂ ♂ and old ♀ ♀ all chicks that hatched fledged, and a greater number of fertile eggs was produced in this mating combination than in any other. Fledging and nesting success were highest in the city, followed by the natural and nursery areas. City nests suffered a lower predation rate than those in the other 2 habitats, but a higher percentage of city nests was abandoned. Overall, the city was the most successful nesting habitat. In the natural habitat 74.1 of nests were built in shrubs, trees being used exclusively in the nursery and city. Maple was the most commonly used tree in all 3 habitats; whereas 67.9% of all nests built in maple failed in the natural area, only 22.2% failed the city. Heights above ground at which nests were built also increased with reliance on trees. City nests were significantly higher than those in the other 2 habitats. Six 2nd broods were raised from the 9 nests in which second broods were attempted. Old ♂ ♂ were known to have been responsible for 6 of these 9 nests. The latest date for the laying of a second clutch following the rearing of a first brood was 16 August. In all but 2 nests the 2nd clutch was laid before the first brood left the nest. Replacement clutches were laid by ♀ ♀ that had lost the 1st nest. The mean time between the loss of the 1st nest and the laying of the 1st egg of the new clutch was 6.9 days. The latest date on which the 1st egg of a replacement clutch was laid was 21 August. All replacement clutches were smaller than 1st clutches. Renesting proved successful in 60% of the cases. Whereas double—brooded birds produced a man of 7.3 fledglings/pair, renesting birds produced 2.8 fledglings/pair. Banding data showed that goldfinches commonly changed mates from year to year. Whereas ♂ ♂ were likely to change their nesting area, ♀ ♀ remained faithful to their original nesting area in subsequent years.

Pear, Pear Psylla Control, 1977

Abstract A three-year-old pear block was divided into eight tree plots replicated three times in a randomized complete block design. The Morestan treatment was first applied at the white bud stage April 19. The two Ambush treatments were applied June 9 but 2.2 in. of rain fell before these treatments dried. All seven treatments were applied or reapplied on June 13. Treatments were applied dilute to runoff with high pressure handgun sprayer at 425 psi using ca 1.2 gal per tree (225 gal/acre). Treatments were evaluated by sampling four spurs per plot and counting all pear psylla nymphs and eggs on each spur under a binocular scope in the laboratory. The pre-treatment count on June 8 indicated a good 2nd brood nymphal population was present. Post-treatment counts were made June 17 and July 11.

Control of Phyllonorycter crataegella in Eastern New York12

Methomyl, endosulfan, demeton, and chlordimeform hydrochloride were highly toxic to adult Phyllonorycter crataegella Clemens in laboratory tests. Endosulfan and endosulfan + pyrethrin also were effective in field treatments applied during moth flight. Methomyl and oxamyl were the most effective insecticides screened for control of the larvae. Because of the present inability to predict the necessity or effectiveness of prophylactic spring brood or 1st brood moth sprays, it is suggested that growers assess the severity of 1st and 2nd brood larval infestations before applying control measures.

Seasonal occurrence and parity of Aedes canadensis (Dipteria: Culicidae) in New York State, U.S.A.

Larval and adult mosquito surveys, conducted in woodland habitats near Ithaca, N. Y., during a summer of excessive precipitation (1972) and one of more normal rainfall (1973), revealed differences in the seasonal occurrence of Aedes canadensis (Theobald) larvae, times of adult emergence, and seasonal parity. A 2nd larval brood of Ae. canadensis occurred in woodland pools during July 1972. Percentages of parous specimens in 1972 were consistently lower than percentages computed for 1973; the lower parity values were probably due to the influence of inclement weather and heavy rainfall. With the exception of a sharp decline in percentage parous following the 2nd brood in 1972, a gradual and uniform increase in parity was observed during each season. Females were easily collected through mid-August of each year, but during 1972 this mosquito was a major nuisance in woodland habitats from late June through late July.

Pears, Pear Psylla Control, Hudson Valley, 1976

Abstract A six-year-old Bartlett pear block near New Paltz, New York was divided into three-tree plots replicated three times in a randomized complete block design. Eleven treatments were applied to run off on June 9 by high pressure handgun sprayer at 400 psi. Treatments were evaluated by sampling five spurs per plot and counting all pear psylla nymphs and eggs on each spur under a binocular scope in the laboratory. A pre-treatment count made June 4 indicated 2nd brood nymphs were starting to hatch and egg-laying was heavy. Counts were made 6 (June 15), 14 (June 23), and 28 (July 6) days after treatments were applied.

Correlations Between Phenological Events and European Corn Borer Activity

The seasonal development of the European corn borer, Ostrinia nubilalis (Hübner) was studied in the Hudson Valley of New York from 1973 through 1975 in relation to the phenological events of selected woody and herbaceous perennial plants. Adult occurrence periods—the initiation of 1st brood flight, peak 1st brood flight, approach of inter-brood, initiation of inter-brood, initiation of 2nd brood flight and peak 2nd brood flight—were selectively correlated with various phenological events of 10 plant species. General relationships among phenological events of 14 plant species and 6 pupal occurrence periods were also found. Observance of the phenological events should forecast the occurrence of each European corn borer period in areas of the Northeast where the indicator plants and insect occur together.

Breeding ecology of the House Swallow, Hirundo rursica

The House Swallow, Hirundo rustica, first arrives S. Japan in mid. March and the main flock occurs in Honshiu in early April. 2. In Hachioji, Tokyo, the peak of nesting is mid. April, the earliest 31 March. The percent nesting was 8% and the nesting period 8 days. Sixty percent of pairs used the old nests; worked for nesting chiefly during the forenoon and harder they worked for new nest. 3. The peak of laying occured in late April, the earliest the 8th. The clutch size 3-7, with the mean 5, and larger in the first broods. 4. The egg is laid daily between 5-7 a. m. 5. The egg size measured 21×15cm, 1.4g. 6. The peak season of hatching was late May. The incubation period was 14 days for the 1st and 12 days for the 2nd broods; the average brood size at hatching 4.7. 7. The feeding frequency per hour was average 32 times during the for-and 27 times afternoon. 8. The chick's weight was: 3rd day 5g., 6th day 12.5g, 9th day 16.7g. and 15th day 19.4g. The adult weigh 18g. 9. The chicks flew most in mid. June, early example on 20 May. They flew from nest led by a parent on fine day between 10-12 a. m. Average flying brood size 4.5 chicks; the fledging period was 21 days for both 1st and 2nd broods but when counted from the date of the laying of 1st egg, it was 39 days for the 1st and 36 days for the 2nd broods. 10. The percent damage from total of eggs laid was 27%. 11. The banding resulted 9.1% recovery of adults and 1.4% of young birds.

Field Studies on the Grey Starling, Sturnus cineraceus Temminck I (continued)

By addition of 1956 observations, this report alters and supplements the resume 4-6 in the Misc. Rep., No. 7, p. 289 as follows:1. Daily winter feeding range (rice paddies) of the flock roosting at Shinhama is delimited to 12km at the most by hills and scattered villages, while Koshigaya flock in a wide field (30km north of Shinhama) covers 20km, its periferal flocks meeting with those of Shinhama at the east of Tokyo. The feeding density ('lowest density') ranged from 0.4 to 4 birds per 1 ha.2. Number of breeding pairs is given by each subarea studied, and the factors influencing the breeding density or preference are discussed. Chief factors may be: 1) enough nesting hollows, 2) type and age of vegetation, 3) structure of feeding area (at least some rice paddies) and 4) safety, etc.3. Rice paddies become unfit for feeding area as the transplanted rice grows. This happens after the young of the 1st brood joined the flock and thus, only few early 2nd broods could be raised (Of the 19 nest-boxes, 17 were used in the 1st and 3 in the 2nd broods; more should be raised in city zone). Then the flock finally moves to the northern field.4. As season advances, the condition of feeding ground changes by cultivation. Varieties in the insect fauna contained are shown by several sample collections made at different places and dates. Early in season, the ground spiders are dominant everywhere, but the most important food for raising young is the mole-cricket (Gryllotalpa), which is best sought in the paddies ready for rice transplantation in late June, when the nestlings grow and leave the nest. This may be said to support Lack's theory of anticipatory adaptation.5. Preliminary consideration is given on the method of determining the ecological niche of the starling quantitatively. The quantity of food taken in a day (or an hour) within a unit area by a flock of starling occurring in a study area may be culculated by: L=Nnt/A×W When N: the number of individuals of the flock, n: the times (frequency) of occurrence of the flock in a day (or an hour), t: length of one feeding stay (mean) of the flock in a study area, W: quantity of food taken by one starling within a unit time (1min., 10min., etc.), A: dimension of study area. In breeding season N, n are substituted by the total number of individuals coming in from the colony. Discussion is given of the method of observation and culculation of t and W, and the method to estimate the quantity of food taken by parent birds was suggested from feeding behavior and the time of absence at the nest site.