bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of organic contamination based on depth stratification in Maninjau Lake, Indonesia
Authors: Komala P S , Nur A , Nazhifa I
Published: September 2019

The purpose of this study was to analyze the organic content of Lake Maninjau based on depth stratification and its organics carrying capacity. Sampling was carried out at the location of lake utilization, namely in the lake center, settlement, hydropower, endemic fisheries, and fish cage following Indonesian National Standard SNI 6989.57: 2008. The parameters measured were BOD5, COD and environmental condition such as pH, DO and temperatures. Lake Maninjau generally is polluted, especially for organic pollutants characterized by the BOD5and COD values that did not meet the quality standard of Government regulations the Republic of Indonesia Number 82 the year 2001 class 2 according to its designation namely 21.87-47 mg BOD/L and 35.2-74 mg COD/L. Using one-way analysis of variance (ANOVA) at 0.05% level of significance both BOD5and COD has a strong correlation with depth of the lake, at hydropower and endemic fisheries. At the shallow lake depths, water is easy to mix so that the organic matter distributed vertically. Fish cage has the highest contribution to the contamination of organic matter in the lake.
Study of recycling potential of solid waste of tourist area in Pariaman City
Authors: Aziz R , Mira
Published: September 2019

This study aims to measure and analyze the data of solid waste generation, composition and recycling potential of the tourist area of Pariaman City. Sampling and determination of samples based on SNI 19-3964-1994. Sampling location was on three beaches in Pariaman City were Gandoriah Beach, Cermin Beach, and Kata Beach, and one island namely Angso Duo island. The results showed that the average unit of solid waste generation was 0.033 kg/cap./day or 0.344 liters/cap./day. The largest component of the waste was organic waste by 90.79%, while inorganic waste by 9.21%. Recycling potential consists of non-ferrous metal 95.072%, plastic 93.359%, glass 64.505%, food waste 36.787% and paper waste 19.231%. It was recommended that solid waste could be treated by composting technology to treat the garbage, cleaning and packing the rubbish, and utilizing the waste that has value to produce the creative product for supporting the tourism activity such as souvenirs.
The effect of additional vegetables and fruits waste on the quality of compost of cassava chip industry solid waste on takakura composter
Authors: Dewilda Yommi , Aziz Rizki , Handayani Restu Ayu
Published: September 2019

This study aims to determine the optimum raw material composition on an aerobic composting method using takakura composter. Each variation was tested for maturity and quality of compost then compared with SNI 19-7030-2004 on macro element parameters. This research mixes raw materials, namely solid cassava chips industrial waste in the form of cassava peel and domestic organic waste in the form of vegetable and fruit waste from the homes of residents around the cassava factory and the addition of EM4 bio-activator. The raw materials used are Cassava Peel (CP) and Vegetables Fruits Waste (VFW) and additional EM4 as bio-activator. The composter used has a capacity of 5 kg as many as 7 units with 7 variations, namely variation 1 (100% CP), variation 2 (100% CP; EM4), variation 3 (90% CP; 10% VFW; EM4); variation 4 (80% CP; 20% VFW; EM4), variation 5 (70% CP; 30% VFW; EM4), variation 6 (60% CP; 40% VFW; EM4), and variation 7 (50% CP; 50% VFW; EM4). The results showed that all composters had met the standards following the compost standards used in Indonesia, namely the SNI 19-7030-2004 standard on compost specifications from domestic organic waste. The quantity of compost produced in this study was 1.0-1.5 kg where variation 6 produced the most compost quantity as 1.5 kg. The optimum dosage for composting was assessed from the highest scoring system was variation 6 with a mixture of 60% CP; 40% VFW; EM4 with a score of 24 and composting time for seven days.
Spatial distribution of coliform bacteria in Batang Arau River, Padang, West Sumatera, Indonesia
Authors: Helard D. , Indah S , Wilandari M
Published: September 2019

The objective of this study was to assess spatial distribution of bacterial population in Batang Arau River. The river water was sampled biweekly, during 3 successive months, and analyzed for coliform bacteria (total coliforms, TC, and fecal coliforms, FC). The results showed that the number of TC range 2.61 – 4.89 log10 number/100 mL and FC 2.48 – 4.79 log10 number/100 mL. The concentration of all parameters inspected has increased from upstream to downstream of the river, except for pH and DO. Bacterial coliforms were strongly correlated with some physicochemical parameters (TSS, TDS, EC and pH), with a Spearman correlation coefficient (r) ranged from -0.599 to 0.827. Analysis of the spatial distribution of the one-way ANOVA at 95% confidence level showed that there were significant differences (p<0.05) in the concentration of bacterial coliforms between upstream and downstream sampling stations as a result of differences in land use and human activity. Cluster analysis grouped 8 sampling stations into two clusters, moderate and high polluted, based on similarities of bacterial characteristics. The bacterial data clearly shows that human health is at a very high risk, as WHO guidelines classification for FC or E. coli in water supplies (WHO 1997) or for agriculture use (WHO 2006) and those strategies for improving water quality of Batang Arau River must be expeditiously implemented.
The determination of workspace and the performance evaluation of PRoM-120 with 3 and 4 kinematic constants
Authors: Adriyan  , Sufiyanto
Published: September 2019

This paper presented a parallel robotic manipulator having combined DOF, i.e., one translational and two rotational DOF, called PRoM-120. PRoM-120 is constructed by using 2PRU/PRS kinematic chains (KCs) and arranged in an asymmetric configuration. The objective of the research is to determine the workspace and to evaluate the performance of PRoM-120 for three cases based on the numerical values of its kinematic constants. The workspace is calculated by applying the discretization method. The inverse kinematic solution, direct singularity, inverse singularity, and actuators limit are taken as the significant factor to determine the workspace. Meanwhile, the performance of PRoM-120 is evaluated by applying conditioning index and transmission based index. It shows the conditioning index cannot be used for PRoM-120, or parallel manipulator having combined DOF. Assessing the performance of PRoM-120 using transmission based index exposes only less than 20% of the workspace be in the good transmission workspace.
Thermal characteristics and phase transformation of iron ores containing varied crystalline water with coal mixtures
Authors: Sinuhaji M M F , Harjanto S , Hapid A
Published: September 2019

Iron ore, with high combined water such as goethite, is widely spread in Indonesia. This is not commonly used as the main raw material in iron and steel making pr0Cess. However, as iron ore resources are getting limited and decreasing in number, iron making industries have to seek other iron ore sources, such as low-grade iron ore goethite ore. The purpose of this research is to investigate the thermal characteristics of composite iron ore containing high combined water, coal, and synthetic goethite ore as comparing samples using the thermogravimetric method. This research is conducted with several experimental conditions: heating from 25-1200°C; heating rate 10°C/minute; nitrogen (inert) furnace atmosphere. The composition is divided into two parts, which are composite A and composite B with 24% and 16% coal, respectively. The results showed that wustite and solid iron formations at a temperature of 973°C; 1050°C and 990°C; 1060°C, respectively. This is because there is more coal composition on composite A so that composite B needs a higher temperature to produce CO as reducing agent. In general, for all mixtures, the reactions 0Ccurred from lower temperature are dehydration, dehydroxylation, the formations of Fe2O3 (hematite), Fe3O4 (magnetite), wustite (FeO), and Fe Metal.
Sound absorption characteristics of the natural fibrous material from coconut coir, oil palm fruit bunches, and pineapple leaf
Authors: Rusli M , Irsyad M , Dahlan H , Gusriwandi  , Bur M
Published: September 2019

In this paper sound absorption characteristics of three kinds of natural fiber composite is evaluated. The fibers are made from coconut coir, oil palm fiber from empty fruit bunches, and pineapple leaf. The sound absorption coefficient is evaluated using a specimen thickness of 10 mm and 20 mm and two variants of fiber density. A simple impedance tube with two microphones is used in the measurement. The sound absorption coefficient is calculated by the transfer function of the two microphones within 200 Hz to 3000 Hz frequency range. It is revealed that three types of fibers can reduce reflected sound in relatively higher frequency. Denser and thicker of a fibrous material increases the sound absorption of the material and shifts the peak of the absorption coefficient into a lower frequency. Furthermore, pineapple leaf fiber has the highest sound absorption coefficient among others type of fibers. Smaller and uniform fiber diameter has a significant role to absorb sound energy in pineapple fiber. Whereas, coconut coir and palm empty fruit bunches fiber have larger, various and random fiber diameters, that could make the sound absorption coefficient become lower, especially within the frequency range of measurement.
Natural frequencies of twisted cantilever beam
Authors: Malta J , Jefri  , Bur M , Satria E
Published: September 2019

This research is conducted to determine the natural frequencies of a twisted beam with different orientation of principal axes numerically using Autodesk Inventor. Further, the results are compared experimentally. To simplify in the analysis, the twisted cantilever beam is divided into two segments model. The orientation between two segments is simulated and tested variously. The natural frequencies obtained numerically and experimentally are selected only in transverse vibration based on the simulation of each mode shape of the cantilevered beam. In general, the natural frequencies of the simulated cantilever beam and experiment results tend to similar results.
Optimization of matrix compositions of Al2O3, SiO2, Caolin, and CaO on the mechanical properties of a geopolymer composite with short carbon fiber
Authors: Akmal J , Badaruddin M , Ismoyo M K , Yuwono S D
Published: September 2019

Geopolymer is a material synthesized from a base material with a large amount of silica and alumina. Geopolymer can be used as an affordable alternative as a substitute for Portland cement, reducing pollution, and resistant to fire under certain conditions. But pure geopolymer has not been widely used in industrial areas because overall it has low toughness and mechanical properties when compared to metals or ceramics. This research was conducted to produce geopolymer composite material with good mechanical properties and can be applied as a material in making environmentally friendly pipes, by identifying the influence of the composition of the geopolymer base material using the Taguchi method. Generate Geopolymer composites with the addition of Silica Powder and random short carbon fiber have good mechanical properties, from the results of the experiment produced the best flexural strength in T9 specimens with details of the composition of Silica Powder (27 g), Kaolin (55 g), CaO (6 g), and Carbon Fiber (13 gr) with a flexural strength of 41.46924655 MPa and flexural modulus 6 GPa.
The effect of solar water heater performance by variation of the plate shaped
Authors: Harun D , Maulana M I , Akhyar
Published: September 2019

The vital component of a solar water heater system is a solar energy collector which is also known as a heat absorber unit. Solar collectors or heat absorbers can convert from solar radiation energy into thermal energy. So the aims of this study to experiment the increasing of water temperature caused by the variation of the solar water heater collector plate. The methodology of this experiment has variated the shape of the plate absorber from the flat plate collector named as plate collector A (quadrangle-folded), and a flat plate collector called as B plate collector B (triangle-folded). The collector uses a stainless steel plate with a dimension of 1.5 × 0.8 m where each collector has a variety of plate folded. Fluid flowed through a 1 inch (diameter) copper pipe with 1.4 m of length and isolated using rubber to minimize wasted heat. The results show that flat plate collector B has a higher efficiency compared to the flat plate collector A. The highest of fluid output temperature found in collector B at 67 °C and a solar intensity is 1198 W/m2. The highest useful energy is 209.91 Watts at 13.30 WIB (Western Indonesia time), and the highest efficiency is 16.23% at 13.00 WIB (in collector B).
Analysis cutting forces and surface roughness of fibre reinforced polymer for end mill processes
Authors: Ridwan F , Havendri R , Susanti O , Gusriwandi  , Yulhizhar
Published: September 2019

This study aims to determine the cutting force characteristics when cutting composite workpieces material. Cutting force is one of the cutting conditions that can determine the machinability of the workpiece. Composites have different mechanical properties from metals thus the machinability characteristics of composites will also be different compared to metals. In this research, cutting force of two GFRP workpieces consisting of chopped strand mat and woven roving type glass fibers with resin matrix was measured using a dynamometer and recorded using DAQ then the surface quality of the workpieces was analyzed. The cutting force and surface roughness characteristics are then compared to the cutting force of Perspex and Aluminium workpieces. The results show that the average cutting force measurement (Ftm) of GFRP Chopped strand mat, GFRP woven roving, Aluminium, and Perspex were 146.8845 N, 103.3915 N, 97.6002 N and 65.33 N resulting in surface roughness of 3.8511 µm, 5.2733 µm, 6.127 µm, and 6.23 µm respectively.
Surface characterization of the ceramic coating process on aluminum matrix composite reinforced particulate
Authors: Sukma H , Rahmalina D , Sulaksono B , Pane E A
Published: September 2019

Particulate-reinforced aluminum matrix composite for automotive components are developed since they have light density, high strength, and hardness, wear-resistant properties also low heat expansion coefficient compared to ferrous metals. An important factor that influences the composite characteristics is the condition of the interface area between the particle and the aluminum matrix with optimal wettability and minimal cavity defects. This research aims to improve hardness on particulate-reinforced aluminum composite which produces by a squeeze casting manufacturing process and ceramic coating process. Steps of this research include the development of an aluminum matrix composite manufacturing processes, which is followed by a ceramic coating process. Matrix composite material made of Al-7Si-9Zn-6Mg matrix with strengthened of 10% alumina (Al2O3) and 10% silicon carbide (SiC) particles, while for coating materials using Chromium Oxide, Aluminum Oxide, and Ez Zirconium. The results of the hardness test without the ceramic coating process are an average of 71 HRB (127 HV). After the coating process, an obtained hardness value of 163 HV for coating material of Chromium Oxide, 373 HV for Aluminum Oxide, and 338 HV for Ez Zirconium. The wear resistance test results in abrasion values of 2.222 x10-6 mm2/kg for coating materials of Chromium Oxide, 1.633 x 10-6mm2/kg for Aluminum Oxide, and 7.021 x 10-6mm2/kg for Ez Zirconium.
Mechanical properties of mild steel by adding Theobroma Cacao Peels Extract (TCPE) inhibitor
Authors: Yetri Y , Gunawarman  , Hidayati R , Zamri A
Published: September 2019

The ability of corrosion inhibitorTheobroma cacaoPeels Extract (TCPE) has been tested to improve the mechanical properties of mild steel after corrosion occurred. These properties were examined to measure its hardness, tensile and fatigue. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) was used to analyze the morphology of the surface. The corrosion rate was found reducing, on the contrary, the efficiency was increasing as the increasing concentration on the extract. This raising was followed by an increase in mechanical properties, namely hardness, strength and fatigue strength. Indeed, the presence of absorption on the surface of the data was reinforced by EDX, X-ray photon spectroscopy (XPS), and AFM for topography. The addition of polar extract of cacao peels in HCl 1.5M is very useful to reduce the corrosion rate on the mild steel surface, and it can retain its mechanical properties after the corrosion occurred.
In vitro of Mg-1.6 Gd alloys after hot extruded for biomaterial application
Authors: Susanti O , Bachtiar E W , Harjanto S , Gunawarman
Published: September 2019

Mg-1.6Gd (wt%) alloys have attracted interest in biodegradable implant materials because of the potential to eliminate secondary surgeries. The purpose of this study was to evaluate the in vitro degradation performance of the alloys after the thermo-mechanical process (hot extruded and hot rolled) and to determine whether the materials are sustainable for further investigation. The performances of the Mg-1.6Gd alloys was using cell viability (MTT) test during the experiment. The results showed that verified viable the osteoblast cell on all the different thermo-mechanical process and no obvious toxic effect within the various time.
The Effects of the distance between ground-sill and double cylinder-piers against the scour patterns
Authors: Mera M , Thaahaa M
Published: September 2019

Flood disaster causes local scouring around the bridge piers. Some efforts to protect piers locally have been widely practiced, but the protective effect is only temporary. This is due to the riverbed being degraded within a few years, and eventually the pier protector is also broken. Ground-sill has a dual function of setting the ground level of the channel and stopping local scouring on the pier to continue. The present study is about physically modelling in the laboratory to observe scour depths due to the distance between the ground-sill and double piers. The position of the double piers remain, i.e. a line of flow direction, so there are upstream pier (called pier 1) and downstream pier (called pier 2). Only the ground-sill positions are varried. The ground-sill is located on the downstream of the pier 2. Some experiments are conducted to get the two best positions of the ground-sill by trial and error, that is W
1 (position 1) and W
2 (position 2) using the biggest discharge flow that can be. The position W
1 is better than W
2. This is based on two criteria: the scour depth has to be stable (no more scour) at the specified time range (0 - 120 minutes), and the maximum scour depth formed has to be the shallowest among those in the other experiments. The resulting two best positions of the ground-sill are then tested with three variations of discharge to observe the scour depth, and to observe the differences of the scour depths due to both piers in point 1 (behind the pier 1), point 2 (right side of the pier 1), point 3 (left side of the pier 1), point 4 (in front of the pier 1), point 5 (behind the pier 2), point 6 (right side of the pier 2), point 7 (left side of the pier 2), and point 8 (in front of the pier 2). The experimental results show that the maximum scour depth with the position W
1 occurs in points 1 and 3 with a 2.9 cm deep and a maximum flow of 3.161 l/s. Meanwhile the maximum scour depth with the position W
2 occurs in point 1 with a 3.8 cm deep and a maximum flow of 3.254 l/s. The scour characteristics with the point W
1 is that a local scouring occurs significantly since the beginning of the flow, but channel bed has been stable since several minutes after the flow starts overtopping the ground-sill. The flow with the position W
2 shows that the backwater affects significantly the flow condition so that scour and sedimentation process continuously occur. This experimentation also confirms that the control slope (the slope between riverbed where the piers are and the top of the ground-sill) has a optimum distance. In this study the optimum control slope is −0.014.
Analytical Network Process (ANP) for priority setting of strategic roads handling at Tebo Regency
Authors: Yosritzal  , Permana J , Istijono B , Hidayat B , Ophiyandri T , Gunawan H
Published: September 2019

Development of transportation infrastructure in the region aims to meet the needs of the community to facilitate mobility of people, goods, and services. However, the work of transportation infrastructure requires a large amount of cost while the development budget is limited. Therefore, a careful determination of the priority of road handling is urgently required. In this study, an analysis was conducted to determine the priority of handling strategic roads in Tebo Regency. This study uses the Analytic Network Process (ANP) method with 4 (four) criteria to determine the priority of road handling, namely: engineering, economics, regional potential, and policies. It was found that National Road - Pintas being the first priority with a weight of 0.252, then the second priority for National Road - Lubuk Mandarsah with a weight of 0.23.The third priority is Unit I Rimbo Bujang - Unit XI Rimbo Ulu Road with a weight of 0.211.
Simulation of the effect of floodway on Batang Kandis River flood control
Authors: Junaidi  , Marona S , Dalrino
Published: September 2019

Floods often occur in Padang City, mainly in the areas of Pasia Nan Tigo Village and Lubuk Buaya Village, caused by the overflow of Batang Kandis when heavy rains occur (intensity of rainfall >15mm/hours). To decrease the river overflow an artificial canal with 300 m long and 50 m wide (floodway) was constructed to bypassing the river flow from the Batang Kandis River to the ocean. In order to find out the effects of the floodway, four scenarios are performed the scenario 1 and 2 were the simulation condition of Batang Kandis River before and after the construction of floodway. While to increase the effectiveness of floodway, simulations 3 and 4 were carried out. Scenario 3 was the combination of floodway with normalization and embankment. To prevent the entry of seawater into the Batang Kandis River, because the floodway is affected by the tide of the sea, then 3-door motion weir was simulated namely scenario 4. Scenario 4 was the combination of floodway normalization, embankment, and a 3 door motion weir. From the simulations, we found that the floodway was effective to decrease the water surface level up to 15 m and 20 m during 10 years and 25 year return period of discharge respectively. From the scenario 3, we found that the embankment with 1.5 m and 2 m was effective to prevent overflow by 10-year and 25-year return period of discharge respectively. While for scenario 4 the water level rises 0.5 m due to motion weir So, that it is needed to extend the embankment with 0,5m high.
Intersection performance evaluation and designing intersection at concourse between arterial road and ramp of Medan-Kualanamu-Tebing Tinggi Highway
Authors: Amrizal  , Harahap A H S
Published: September 2019

In overcoming congestion problems that occur in Medan-Tebing Tinggi route, especially at certain points such as at Pasar Bengkel and Kayu Besar intersection during peak hours, an infrastructure has been built in, that is a highway which connecting Medan-Kualanamu-Tebing Tinggi. Medan-Kualanamu-Tebing Tinggi highway (MKTT) will connect Medan City and Tebing Tinggi City, so that drivers from Medan who will go to Tebing Tinggi will not pass through the main road that is prone to congestion.

There is an intersection that connects arterial roads with each MKTT toll gate. At the intersection, there is a conflict between flows from the opposite direction and intersecting, resulting in delays and queues along the intersection arm. The conflict occured because of the lack of designing of the intersection that drains the flow of vehicles from ramp to arterial road or vice versa. This needs consideration because of the congestion causes queues and delays, especially during peak hours and holidays, so that it requires intersection performance analysis at concourse between arterial road and ramp of Medan-Kualanamu-Tebing Tinggi highway and design the geometric of intersection which appropriate with this intersection.

From the results of the evaluation analysis, obtained degree of saturation at the intersection of the arterial road and the ramp of Lubuk Pakam toll road at 0.71 with level of service C that is still feasible to be used, so there is no need to change the intersection geometry. While for Sei Rampah, the degree of intersection saturation is 0.79 with the level of service D, which means that it is not feasible, requiring a change in the geometry of the intersection with a signalized roundabout. With the planned roundabout geometry, the degree of saturation is 0.5 which means it is feasible to use.
Shear behavior of fly ash reinforced concrete beam without shear reinforcement
Authors: Nasution A E , Kurniawan R , Thamrin R
Published: September 2019

An experimental study was carried out to discover the shear behavior of reinforced concrete beam (RCB) using fly ash (FA) as cement replacement material. Variation of FA composition that was used as the research variable were 10 %, 20 % and 30 % by cement mass. Each of the variations has two RCB specimens while two RCB specimens used normal concrete (non FA) as control beams. The beam was reinforced only in the longitudinal direction without shear reinforcement. The beam was tested by the static monotonically loading method. The results showed that the shear strength of RCB decreased by increasing the amount of FA.
Evidence for a Previously Unrecognized Species of Owlet-Nightjar
Authors: Pratt Thane K.
Published: September 2019

I studied the systematic relationships of the three large owlet-nightjars (Aegothelidae) to determine the taxonomic status of a fawn-colored lowland form currently classified as Aegotheles insignis tatei. I examined most of the existing specimens of A. i. insignis (n = 158) and A. crinifrons (n = 23) and all known specimens of A. i. tatei (n = 4). I also examined specimens of A. albertisi (n = 70), A. archboldi (n = 25), A. bennettii (n = 55), A. cristatus (n = 50), A. savesi (n = 1), and A. wallacii (n = 21). Aegotheles i. tatei was distinguishable from A. i. insignis and A. crinifrons by its small size and in seven plumage characters. Aegotheles i. tatei was further distinguishable from one or the other of these taxa by four additional characters. Unique among owlet-nightjars, A. i. tatei has the shortest tarsi, does not have recurved filamentous tips on its facial feathers, and has stiffer feathers on the auricular area and throat. My search of museums revealed two new specimens of A. i. tatei, expanding the known geographic range of this taxon 1,000 km eastward along the southern coast of Papua New Guinea from the upper Fly River to Nunumai, near the Ulamanu River. Unlike the montane A. i. insignis, A. i. tatei inhabits lowland forests where rivers emerge from foothills of the main cordillera. I propose that tatei be elevated to species status and that the name Starry Owlet-Nightjar be adopted based on the bird's markings. Aegotheles crinifrons, A. insignis, and A. tatei pass through a previously unrecognized but distinctive rufous juvenal plumage. These are the only owlet-nightjars known to exhibit this plumage, which calls for reexamination of generic limits within the Aegothelidae.
Seasonal, Age, and Sex-Related Variation in Fatty-Acid Composition of Depot Fat in Relation to Migration in Western Sandpipers
Authors: Egeler Oliver , Williams Tony D.
Published: September 2019

The composition of depot fat in Western Sandpipers (Calidris mauri) was dominated by C16 and C18 fatty acids (palmitate, 16:0; palmitoleate, 16:1; stearate, 18:0; oleate, 18:1), which together comprised 80 to 90% of all fatty acids analyzed. Significant seasonal variation occurred in the relative proportion of specific fatty acids and the ratio of saturated to unsaturated fatty acids in relation to the migratory cycle of the sandpipers. In adults of both sexes, the proportion of 16:0 and 18:0 fatty acids decreased from winter (December) to premigration (March) to spring migration (May), whereas the proportion of 16:1 and 18:1 fatty acids increased over these same periods. Consequently, total unsaturated fatty acids increased by 34% between the winter and premigratory phase, and by a further 22% between premigration and spring migration. Therefore, biochemical modification of adipose tissue in Western Sandpipers begins during the premigratory period in preparation for long-distance flight but continues as migration progresses, perhaps reflecting a training component of physiological modulation for migration. Juveniles showed similar changes to adults in the composition of their depot fat during the “premigratory” period, even though most juveniles do not undergo hyperphagia or rapid fattening at this wintering site. Potential prey species collected from a wintering site in Panama had a higher proportion of saturated fatty acids, less 16:1 and 18:1, and more 18:0 fatty acid compared with those from a migratory stopover site in British Columbia, paralleling the seasonal changes in depot fatty-acid composition observed in Western Sandpipers. However, the fact that Western Sandpipers show an increase in level of unsaturation and in the amounts of 16:1 and 18:1 fatty acids in their fat stores on the wintering ground prior to migration suggests that seasonal variation in fatty-acid composition is not entirely diet dependent.
Influence of Niche Overlap and Territoriality on Hybridization Between Hermit Warblers and Townsend's Warblers
Authors: Pearson Scott F. , Manuwal David A.
Published: September 2019

Hybrid zones between Townsend's Warblers (Dendroica townsendi) and Hermit Warblers (D. occidentalis) in the Pacific Northwest are narrow relative to estimated dispersal distances and appear to be moving, with Townsend's replacing Hermits. We examined whether the habitat-transition and parental-fitness asymmetry models can explain why these zones are narrow and moving by comparing habitat variables associated with warbler territories in the Washington Cascades hybrid zone. Habitat variables did not differ among phenotypes, suggesting that the habitat-transition model cannot explain the narrow and dynamic nature of this hybrid zone. Habitat characteristics of Hermit Warbler territories did not differ inside versus outside the hybrid zone, also suggesting that this zone is not associated with a region of habitat transition. The lack of difference in habitat use could be the result of comparing variables that are not important to pairing success. However, warblers tended to select territories on west-southwest aspects. South aspects in the southern Washington Cascades are dominated by Douglas fir (Pseudotsuga menziesii) and true fir, which is a habitat selected by female warblers when choosing among territories and males. The parental-fitness asymmetry model does not necessarily make predictions about habitat use within the hybrid zone but predicts the superiority of one parental species over the other. However, if significant overlap occurs in habitat use or niche (as in these warblers), then competition between parental species is likely to occur. To determine whether these species compete, we mapped 12 warbler territories and monitored an additional 94 territories throughout the breeding season and found that all males with neighbors compete for and hold exclusive territories. Thus, the pattern of habitat use and territoriality is consistent with the parental-fitness asymmetry model.
Effects of Population Density on Survival in Merlins
Authors: Lieske David J. , Warkentin Ian G. , James Paul C. , Oliphant Lynn W. , Espie Richard H. M.
Published: September 2019

Accurate estimation of survival probabilities is an important component of population demographics, and it permits a test of the life-history prediction that densities influence population dynamics via suppression of survival rates. As part of a long-term study of urban-nesting Merlins (Falco columbarius), we estimated survival rates and tested for the effects of density dependence based on capture histories from 1,354 individuals (43 males and 110 females caught for the first time as adult breeding birds, and 597 males and 604 females caught for the first time as locally produced nestlings). Overall capture probabilities were 0.55 ± SD of 0.039 per year for adults, 0.10 ± 0.075 per year for juvenile males, and 0.58 ± 0.23 per year for juvenile females. Mean survival rate of adults was 0.62 ± 0.11 per year and did not differ significantly between males and females. Overall juvenile survival rates were 0.23 ± 0.032 for males and 0.055 ± 0.012 for females. Band returns suggest that the discrepancy in survival rates between juvenile males and females resulted from higher natal dispersal of females rather than from lower survival. Survival of adults (but not juveniles) was negatively density dependent, suggesting that density-dependent declines in survival exerted a regulatory effect on population size.
Reproductive Success of Wood Thrushes in Forest Fragments in Northern Indiana
Authors: Fauth Peter T.
Published: September 2019

I monitored 278 Wood Thrush (Hylocichla mustelina) nests in 14 forest fragments (range 7 to 500 ha) in northern Indiana to explore patterns of brood parasitism by Brown-headed Cowbirds (Molothrus ater), nest predation, and reproductive success. Density of thrushes was negatively related to area of forest fragments. Cowbirds were common throughout the landscape, but I found no relationship between their abundance and forest area. Overall, 90% of the thrush nests were parasitized by cowbirds (x̄ = 2.4 cowbird eggs per nest). The number of cowbird eggs per thrush nest was not related to forest area, abundance of host species, or distance to a forest edge but was positively related to thrush abundance. Nest predation rates averaged 58% and were lower than those reported in much of neighboring Illinois but also were unrelated to forest area and distance to a forest edge. The combination of cowbird parasitism and nest predation resulted in relatively low reproductive success (x̄ = 0.6 thrush fledglings per nesting attempt). I estimated that Wood Thrushes in northern Indiana made an average of three nesting attempts per breeding season (based on 17 color-marked females) and had relatively low seasonal fecundity (x̄ = 0.9 female fledglings per adult female per season). Nonetheless, considerable annual variation in seasonal fecundity suggested that some sites exceeded the source-sink threshold in some years. Regardless, the overall landscape appeared to be part of a regional sink for Wood Thrushes, although its negative influence on regional demography was not as severe as elsewhere in the midwestern United States. The poor demographic balance in much of the agriculturally dominated Midwest suggests that conservation efforts for Wood Thrushes and other Nearctic-Neotropical migrants should be directed at preserving and enhancing possible source habitats in regions where parasitism by cowbirds and nest predation are reduced.
Geographic and Ecological Variation in Clutch Size of Tree Swallows
Authors: Dunn Peter O. , Thusius Kevin J. , Kimber Kevin , Winkler David W.
Published: September 2019

In many birds, populations breeding at higher latitudes have larger clutch sizes. It has been hypothesized that this relationship results from the greater availability of food at higher latitudes. We examined geographic variation in clutch size of Tree Swallows (Tachycineta bicolor) in relation to latitude, longitude, laying date, breeding density, elevation, and summer actual evapotranspiration (AE). AE is a measure of terrestrial primary productivity, and we assumed that it was correlated with resource abundance. Clutch size data were compiled from nest records throughout the breeding range in the United States and Canada (n = 7,459). Summer AE estimates were made from long-term climatological records, and breeding density was estimated from Breeding Bird Surveys. All variables were averaged for each 1° block of latitude and longitude (n = 85 latilong blocks). We found a strong positive relationship between clutch size and latitude. Absolute levels of resource abundance (summer AE) were not related to clutch size but were related inversely to latitude and longitude. After controlling for the effects of confounding variables, clutch size was related positively to latitude and relative resource abundance (summer AE after controlling for breeding density). Our results are consistent with Ashmole's hypothesis that relative, rather than absolute, levels of resource abundance determine at least some of the variation in clutch size.
In Memoriam: John Thompson Emlen, Jr., 1908–1997
Authors: Lanyon Wesley E. , Emlen Stephen T. , Orians Gordon H.
Published: September 2019

“My fascination with birds started with a nature study teacher, Miss Trueblood, when I was eight or nine years old. My first notebook presented a systematic list with dates from 1919 when I was ten. It listed 51 species including such interesting identifications as hoot owl, poll parrot, wild duck, petrel, and crane. In 1920 I had 80 species listed, all of them recognizable and more or less correctly spelled. Two years later I was keeping notes on field identification marks and describing songs quite creditably with words and personally devised symbols.”
Use and Selection of Sap Trees by Yellow-Bellied Sapsuckers
Authors: Eberhardt Laurie S.
Published: September 2019

Yellow-bellied Sapsuckers (Sphyrapicus varius) obtain phloem sap from clusters of holes that they peck in living trees. I examined trees that sapsuckers used for sap extraction in northern Michigan and tested several hypotheses to explain why they choose specific trees for attack and why they cluster their holes in one place on the bole of each of these focal trees. Sapsuckers preferentially attacked individuals of paper birch (Betula papyrifera), red maple (Acer rubrum), juneberry (Amelanchier sp.) and bigtooth aspen (Populus grandidentata). They made clusters of sap holes an average of 7.13 m from the ground and within 1 m of a live branch; most clusters were located above old holes or other wounds from previous years. Each new sap incision through the bark to the phloem stream was made above a previous one and was enlarged for an average of 3.1 days before being abandoned for a new, higher hole. The resulting long vertical chains of holes were made alongside others to form tight clusters of holes at a single spot on the tree. Sapsuckers did not select trees for sap extraction based on location relative to nesting sites or on microclimate conditions of water availability and tree density. Individual trees used for sap extraction did not have thinner bark, more moisture in bark samples, or larger crowns, but they did score lower in an index of overall tree health. Experimental evidence suggested that sapsuckers cluster their holes to induce the accumulation of sap in bark that they will attack for future sap extraction. Thus, sapsuckers appear to overcome some of the difficulties in obtaining phloem sap by choosing specific species and individuals, clustering sap holes above previous wounds, and possibly by farming their resource throughout the season by girdling the tree's phloem stream with each successive sap incision. I attempted to duplicate the wounding techniques and patterns of wounding of sapsuckers but was unable to induce sap flow from the same or similar trees in the area.
Ornament Size and Symmetry: Is the tail a Reliable Signal of Male Quality in the Red-Collared Widowbird?
Authors: Goddard Keith W. , Lawes Michael J.
Published: September 2019

Fluctuating asymmetry (FA) may provide a direct test of whether sexual selection via “arbitrary traits” or “good genes” is responsible for the evolution of epigamic traits, because FA is an epigenetic measure of stress during development. However, tests of the FA hypothesis have yielded equivocal results, and the debate between arbitrary traits and good genes continues. The FA hypothesis predicts a negative relationship between ornament size and asymmetry. In non-ornamental traits, a U-shaped relationship between trait size and asymmetry is expected. We tested these predictions in the Red-collared Widowbird (Euplectes ardens) by examining the relationship between size and asymmetry in the length of the tail, tarsus, and wing. We found no significant linear or second-order polynomial relationships between trait size and asymmetry. Furthermore, no relationship existed between asymmetry and two indices of body condition. This suggests that the tail is not a reliable signal of male quality in the Red-collared Widowbird. However, we argue that the assumptions of the FA hypothesis are too simplistic for this conclusion to be drawn with a high degree of confidence.
Divergent Foraging Strategies of Two Neotropical Migrant Warblers: Implications for Winter Habitat Use
Authors: Strong Allan M.
Published: September 2019

To address whether foraging strategies affect habitat-use patterns of nonbreeding warblers, I quantified foraging behavior, bill dimensions, and diet (based on regurgitation samples) of Ovenbirds (Seiurus aurocapillus) and Swainson's Warblers (Limnothlypis swainsonii) wintering in three habitats in Jamaica. Ovenbirds primarily gleaned prey from the surface of the leaf litter (95% of foraging maneuvers), resulting in a diet comprised predominantly of ants (62% of all prey items), seeds (18%), and beetles (9%). Swainson's Warblers foraged by lifting leaves (80% of foraging maneuvers), resulting in a significantly different diet dominated by beetles (39%), spiders (22%), and ants (19%). More than 60% of the regurgitation samples from Swainson's Warblers contained orthopterans and/or gecko (Sphaerodactylus goniorhynchus) bones. Averaged across all habitat types, Ovenbirds consumed ants in direct proportion to their abundance based on visual counts of arthropods. Swainson's Warblers consumed beetles more than expected based on the abundance of beetles in visual counts and Berlese funnels. The use of a diversity of habitats by Ovenbirds may be related to their ability to feed opportunistically on ants, which are a widespread, abundant, and reliable resource. In contrast, based on their foraging behavior and diet, Swainson's Warblers may be restricted to habitats with a well-developed canopy and an abundant subsurface leaf-litter fauna.
A Double-Observer Approach for Estimating Detection Probability and Abundance From Point Counts
Authors: Nichols James D. , Hines James E. , Sauer John R. , Fallon Frederick W. , Fallon Jane E. , Heglund Patricia J.
Published: September 2019

Although point counts are frequently used in ornithological studies, basic assumptions about detection probabilities often are untested. We apply a double-observer approach developed to estimate detection probabilities for aerial surveys (Cook and Jacobson 1979) to avian point counts. At each point count, a designated “primary” observer indicates to another (“secondary”) observer all birds detected. The secondary observer records all detections of the primary observer as well as any birds not detected by the primary observer. Observers alternate primary and secondary roles during the course of the survey. The approach permits estimation of observer-specific detection probabilities and bird abundance. We developed a set of models that incorporate different assumptions about sources of variation (e.g. observer, bird species) in detection probability. Seventeen field trials were conducted, and models were fit to the resulting data using program SURVIV. Single-observer point counts generally miss varying proportions of the birds actually present, and observer and bird species were found to be relevant sources of variation in detection probabilities. Overall detection probabilities (probability of being detected by at least one of the two observers) estimated using the double-observer approach were very high (>0.95), yielding precise estimates of avian abundance. We consider problems with the approach and recommend possible solutions, including restriction of the approach to fixed-radius counts to reduce the effect of variation in the effective radius of detection among various observers and to provide a basis for using spatial sampling to estimate bird abundance on large areas of interest. We believe that most questions meriting the effort required to carry out point counts also merit serious attempts to estimate detection probabilities associated with the counts. The double-observer approach is a method that can be used for this purpose.
Rainfall, Fruiting Phenology, and the Nesting Season of White-Crowned Pigeons in the Upper Florida Keys
Authors: Bancroft G. Thomas , Bowman Reed , Sawicki Richard J.
Published: September 2019

White-crowned Pigeons (Columba leucocephala) varied their timing of breeding and nesting intensity in response to variation in production of the four most important fruit species in their breeding-season diet in the upper Florida Keys. From 1988 through 1990, we monitored fruit production year-round in five habitats in which pigeons foraged and monitored all pigeon nests along two transects on Middle Butternut Key. Annually, pigeon breeding was positively correlated with summer rains and with the peak in overall fruit production. However, within the breeding season, only the availability of Metopium toxiferum was positively correlated with rainfall and the number of new clutches initiated. Both the timing and magnitude of breeding varied annually. In 1988, when Metopium was more available, more pigeons nested, the nesting season started earlier and lasted longer, and a large peak in nesting occurred when Metopium fruit ripened. During 1989 and 1990, when the relative availability of Metopium was lower, fewer pigeons nested, the nesting season was shorter, and the seasonal peak in nesting associated with Metopium fruit was reduced or absent. Nesting patterns did not appear to vary with changes in the relative availability of other fruits. White-crowned Pigeons appear to prefer Metopium fruits to other species. Because pigeons do not supplement nestling diets with arthropods, but augment their diets with protein-rich crop milk, they may depend on lipid-rich fruits such as Metopium to provide the energy for breeding and crop-milk production. Metopium fruit production may be influenced by rainfall and climatic conditions, both of which may vary spatially within the range of White-crowned Pigeons in Florida. Evidence that pigeons shift foraging sites when Metopium availability varies emphasizes the need to preserve large tracts of seasonal deciduous forest in the Keys and to protect Metopium trees in suburban areas where they are removed because they cause contact dermatitis in humans.