A Study of the Nocturnal Spring Migration of Birds at Point Abino based on Radar and Ground Observations

When birds are migrating over the Niagara region, it is possible to see the migration but not individual birds on base reflectivity images produced by the Buffalo Weather Radar. What was not known, when I began my studies, was how intensities on the weather radar images were related to the numbers of birds in migration. If this relation was understood, the weather radar could be used to estimate bird numbers over a very large area. In fact, the many weather radars in various locations in the United States and Canada could be used to monitor bird numbers over the entire route followed by migrants.

I worked on determining the relation between weather radar intensities and numbers of birds aloft, in May 1999. During this period, I operated a small (3-cm wavelength) marine radar on the roof of Brock University, while simultaenously downloading base reflectivity images from the Buffalo Weather Radar. Thus, I was able to compare the intensity of migration based on base reflectivity images with the number of birds seen on the 3-cm radar. I obtained a numerical relation between the two sets of numbers.

This report is divided into seven parts. In Part 2, I present the ground counts of birds and identify the days on which birds seem to have landed in large numbers. In Part 3, I explore the results on bird and insect migration obtained on the 3-cm radar. In Part 4, the evidence for bird migration on the Buffalo Weather Radar is presented. In Part 5, the possible landings seen on the weather radar are compared with the birds seen on the 3-cm radar and the birds observed in ground counts. In Part 6, the relation between the birds counted on the 3-cm radar and the reflectivity on the Bufflao Weather Radar over Point Abino is explored. Finally, in Part 7, the results are summarized and discussed.


The Ontario Spring Bird Migration on Weather Radar: an update

This report is a follow-up to the original article in Birders Journal in 1998 (BJ 7:310-5). In the spring of 1999, from April 20/21 to June 10/11, I operated a small 3-cm radar to count birds above Brock University in southwestern Ontario. The radar is reasonably good at detecting birds in a zone 250 m to 900 m above the ground, but it is not effective above or below these heights. The number of targets that passed over a one kilometre line through the University each night is shown in Figure 1 for heights greater than 250 m and 350 m. There is evidence that insects as well as birds are sometimes present below 350 m; some of the targets detected from 250-350 m are, therefore, not birds. I will begin by discussing the bird migration above 350 m and then return to a discussion of what appears to be occurring at the lower heights.


Radar Studies of the 1999 Spring Migration at Brock University: a comparison of radar data and insect data from pheromone and blacklight traps

In earlier studies using the 3-cm conical radar at Brock University, it became evident that insects might be contaminating the bird numbers obtained in the spring migration. Accordingly, the study in the spring of 1999 focused on establishing if insects were present, and if they were present, whether they could be eliminated from contaminating the bird numbers. Three studies were conducted of which this is the third. The other two, Brock Physics Report, PR-2000-1 and Brock Physics Report, PR-2000-2 deal with the distinction between insects and birds and with the Buffalo weather radar, respectively. The goal here is to see what can be learned about insects on radar and about their migration into Ontario by comparing radar data and insect trap data obtained in the spring of 1999 in the vicinity of St. Catharines, Ontario.

Physics Report, PR-2000-3.


Radar Studies of the 1999 Spring Migration at Brock University: the Buffalo weather radar

In earlier studies using the 3-cm conical radar at Brock University, it became evident that insects might be contaminating the bird numbers obtained in the spring migration. Accordingly, the study in the spring of 1999 focussed on establishing if insects were present, and if they were present, whether they could be eliminated from contaminating the bird numbers. Three studies were carried out of which this is the second. The other two, Brock Physics Report, PR-2000-1 and Brock Physics Report, PR-2000-3, deal with the distinction between insects and birds and with a comparison of radar data and insect data from pheromone and blacklight traps, respectively.
The primary goal of this study is to summarize the base reflectivity data from the Buffalo WSR-88D from April 20/21 to June 10/11, the period when the 3-cm radar was operating at Brock University. The base reflectivity images are gif files created from the Freese-Notis bmp images which were downloaded each hour, 24 hours a day throughout the study period. There are some nights when the WSR-88D Doppler data is also available. In addition to summarizing the base reflectivity, I searched for cases where the WSR-88D image reveals signals which are due to weather but could be confused with birds or insects. Finally, I searched for possible insects on the WSR-88D images in the hours around sunrise. The second goal of this study is to find the relation between dBZ and density on the 3-cm radar. This work was undertaken in collaboration with Ron Larkin and Robb Diehl of the Illinois Natural History Survey. A third goal of this study was to develop a simple technique for estimating the density and migration traffic rate (MTR) of birds from the Buffalo WSR-88D. Finally, I looked in some detail at a single night, May 15/16, when a large movement of birds took place.

Physics Report, PR-2000-2.


Radar Studies of the 1999 Spring Migration at Brock University: distinguishing between insects and birds

In earlier studies using the 3-cm conical radar at Brock University, it became evident that insects might be contaminating the bird numbers obtained in the spring migration. Accordingly, the study in the spring of 1999 focused on establishing if insects were present, and if they were present, whether they could be eliminated from contaminating the bird numbers. Three studies were carried out, of which this is the first. The other two, Brock Physics Report PR-2000-2 and Brock Physics Report, PR- 2000-3, deal with the Buffalo WSR-88D weather radar and a comparison of radar data and insect data from pheromone and blacklight traps, respectively.
The primary goal in this report is to ascertain if we can distinguish between birds and insects on the 3-cm radar during the period of the spring migration of birds. If we can make the distinction then it should be possible to chart the spring migration of birds using the 3-cm radar after the insects are eliminated. A secondary goal is to ascertain if we can distinguish between birds and insects on the Buffalo WSR-88D weather radar during the period of the spring migration of birds. If we can make the distinction then it should be possible to chart the spring migration of birds using the weather radar.
Our final goal, based on the results of the 3-cm conical radar and WSR-88D studies is to produce a chart of night migration totals for the spring of 1999 of what are believed to be birds

Physics Report, PR-2000-1.


The Ontario Spring bird migration on weather radar: How to anticipate good birding days during the spring migration

The weather radars can provide the birder with a general idea of the ups and downs of the spring migration, but how many birds are actually aloft when the migration shows on the weather radars? To answer this question I operated a small conical radar at Brock University. The conical radar detects birds above the university in a small portion of the area that is seen on the Buffalo weather radar. From the conical radar I can estimate the number of birds aloft. By comparing the results from the Buffalo weather radar with those from the conical radar I can calibrate the weather radar to allow estimation of the number of birds aloft.

Birders Journal, 7, 310, 1998.


Comments on "Display of Bird Movement on the WSR-88D: Patterns and quantification."

It is our belief that weather radars are a powerful tool for monitoring the migration of birds in North America. We therefore read with interest the article by Gauthreaux and Belser (1998) dealing with quantification of bird movements using WSR-88D reflectivity data. We wish to note that the approach to the problem of monitoring migration described in the article may be somewhat incomplete. It is our goal to discuss here how the migration could be more accurately estimated using both base reflectivity and Doppler velocity data available from the weather radars.

Weather and Forecasting, 14, 1039-40, 1999.


Surface disordering, roughening and premelting of Ag(110)

Abstract: to come.

Surf. Sci., 374, 9-16, 1997.


Monitoring nocturnally migrating birds using radar and acoustic microphones

At night, during the spring and fall, millions of small birds migrate over southern Ontario. As they fly, they communicate with short call notes or chips, and it may soon be possible for the chips to be counted and identified using sophisticated computer software, recording the migration using an automated system. Such a record would complement radar data which, while it provides data on numbers of birds and their direction of flight, does not allow identification of the birds. My study of migration with acoustic microphones was carried out in the spring and fall of 1994 and repeated in the spring and fall of 1995.

Birders Journal, 5, 75-7, 1996.


Nocturnal migration and the Niagara Escarpment: A comparison of ground observations, data from a weather radar and data from a conical radar

Number densities of birds flying over Brock University were compared with dBZ values over the university on the Buffalo NEXRAD radar. A linear relationship was found between density and z, which is antilog (dBZ/10.0). The relationship between bird densities and z values can be used in the estimation of the number of birds migrating across the region covered by the Buffalo radar. The weather radar can therefore be used for monitoring the numbers of migrants entering Ontario above the Niagara Escarpment each spring. From studies of NEXRAD data from other locations, the numbers of birds entering Ontario in the spring (or leaving in the fall) can be estimated. At sunrise, following nights of bird migration, a strong concentration of birds landing along the south shores of Lake Erie and Lake Ontario was noted on the weather radar. Ground observations of birds along the Niagara Escarpment, following nights of bird migration, were made and are described in the report.

Physics Report, PR-1998-2.


The relation between the number of calls of a nocturnally migrating bird species heard and the actual number of individuals of that species passing overhead

A theory of the relationship between the number of nocturnal migrant calls heard at the ground and the actual number of nocturnal migrants passing overhead is developed. Results of a study of migrant calls with arrays of acoustic microphones, from which the locations of the birds could be determined, are then presented. Finally, the theory developed is used in conjunction with the acoustic microphone data to demonstrate how nocturnal migration traffic rates can be estimated. The key to the estimation is a knowledge of the rate at which birds call when they migrate.

Physics Report, PR-1997-3.


An evaluation of avian acoustic location array accuracy

In several recent studies (1995, 1996) one of the authors (JEB) has calculated d the locations (height, bearing and radial distance from the microphone array) of nocturnal migrants from their calls using time delays obtained from an array of acoustic microphones. A number of assumptions are involved in calculating the locations from the measured time delays. The present study is designed to explore the validity of the assumptions used in the calculations. The exploration is done by determining the location of an artificial sound source using the location array and comparing this calculated location with the measured location of the artificial sound source. In this report, a brief discussion of the data gathering procedure and the method of determining the locations is presented. The results are then discussed in some detail. A number of attempts to understand why the calculated and measured locations of the artificial sound source do not agree are described.

Physics Report, PR-1997-1.


A Study of the height of birds and the range of microphones in the nocturnal migration: New Smyrna Beach, Florida, Spring 1996

In the Spring of 1996 the author and W.E. Evans operated a number of microphone arrays at the airport in New Smyrna Beach, Florida. The microphones detected the calls of nocturnal migrants as they passed over the airport runway. The goals of these microphone studies were twofold. First, to determine the range of the microphones. Second, to determine the height distribution of calling birds in the Florida nocturnal spring migration. In this report the focus is on the data obtained on the night of May 11/12. A discussion of data obtained on the nights of April 30/May 1, May 3/4, May 5/6, and April 26/27 is also included.

Physics Report, PR-1996-2.


Determination of the height of nocturnal passerine migrants from their call notes using an array of four acoustic microphones at St. Catharines, Ontario, Canada, in the Fall of 1995

In the Fall of 1995, the flight calls of nocturnal migrants were recorded on an array of four acoustic microphones at St. Catharines, Ontario. This is a continuation of the study begun in the spring of 1995 and reported by Black and Tucakov (1995). The basic idea underlying this study is to see if one can obtain the location of the bird from a triangulation procedure based on time delays between the calls received at each of the four microphones. The primary goal of the study is to determine whether such a triangulation procedure can be used in studying the migration of nocturnal migrants, more specifically under what conditions it can be used. In Part 1 of this report, I describe the equipment used to record the bird calls and the layout of the microphones. In Part 2, I describe the software used to determine time delays from the audio data. In part 3, I present the results of the fall study, and in Part 4, I discuss the results with emphasis on the usefulness of the procedure and what further studies should be done to obtain a better understanding of where the procedure can be used.

Physics Report, PR-1996-1.


The relation between the number of calls of a nocturnally migrating bird species heard and the actual number of individuals of that species passing overhead

We present calculations of the relationship between the number of nocturnal migrants calls heard at the ground and the actual number of nocturnal migrants passing overhead. In certain cases we show that the factor linking the two quantities is the distance travelled between calls by the birds.

Physics Report, PR-1995-1a.


A Fall Study (1995) of nocturnal bird migrations in southern Ontario using acoustic microphones and radar

In the Fall of 1995, acoustic microphones and a marine radar were operated at Long Point in southern Ontario. The microphones were normally operated for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a VCR. The marine radar was operated for the same time interval on selected nights. A simple video camera was pointed at the radar display screen and its output was put on the VHS tapes. The VHS cassettes obtained were then listened to, and the number of night migrant contact notes or "chips" was recorded for 10 minutes in approximately each two hours. No attempt was made to identify each chip, but the chips were divided into two groups; warblers/sparrows and thrushes/others. This report presents the results of these chip counts. In addition the radar data was examined and the results are presented and compared with the results from the chip counts.

Physics Report, PR-1995-6.


Determination of the height of nocturnal passerine migrants from their call notes using an array of four acoustic microphones

In the Spring of 1995 the flight calls of nocturnal migrants were recorded on an array of four acoustic microphones. The basic idea underlying this study was to see if we could obtain the location of the bird from a triangulation procedure based on time delays between the calls received at each of the four microphones. The primary goal of the study was to determine whether such triangulation procedure could be used in studying the migration of nocturnal migrants, more specifically under what conditions it could be used. In Part 1 of this report we describe the equipment used to record the bird calls and the layout of the microphones. In Part 2, we describe the software used to determine time delays from the audio data. In Part 3, we present the results of the spring study and in Part 4, we discuss the results with emphasis on the usefulness of the procedure and what further studies should be done to obtain a better understanding of where the procedure could be used.

Physics Report, PR-1995-5.


A Spring Study (1995) of nocturnal bird migration in southern Ontario using acoustic microphones

In the Spring of 1995, acoustic microphones were operated at Long Point and St. David's in southern Ontario. The microphones were operated for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a VCR. The VHS cassettes obtained were then listened to, and the number of night migrant contact notes or "chips" was recorded for 10 minutes in approximately each two hours. No attempt was made to identify each chip, but the chips were divided into three groups: warblers/sparrows and thrushes and others. This report presents the results of these chip counts. A marine radar was also operated for 11 days at Old Cut. Preliminary results of the radar study are presented.

Physics Report, PR-1995-4.


A Fall Study (1994) of nocturnal bird migration in southern Ontario using acoustic microphones

In the Fall of 1994, acoustic microphones were operated at Long Point and St. David's in southern Ontario. The microphones were normally operated for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a VCR. The VHS cassettes obtained were then listened to, and the number of night migrant contact notes or "chips" was recorded for 10 minutes in approximately each two hours. No attempt was made to identify each chip, but the chips were divided into two groups; warblers/sparrows and thrushes/others. This report presents the results of these chip counts.

Physics Report, PR-1995-2.


A structural study of Pd/Cu(100) surface alloys

The structures formed by one-half and one monolayer (ML) of Pd evaporated onto Cu(100) at 300 K were studied by low energy electron diffraction (LEED), medium energy ion scattering (MEIS), thermal desorption spectroscopy (TDS), and embedded atom method (EAM) calculations. In the half monolayer case, the LEED I(E) curves are consistent with the established c(2 x 2) surface alloy model. The MEIS data, however, suggest that a fraction of the Pd (~1/4) in in "second layer" sites , in agreement with previous LEIS, TDS and XPS forward scattering measurements. The EAM simulations support the formation of alloy islands, providing a mechanism for the covering of some Pd atoms. As the deposition proceeds, however, this island formation is indicated to occur preferentially over clean copper. In the one monolayer case, a p(2 x 2)-peg LEED pattern is observed. Analysis of the I(E) curves suggests that this arises form (100) Pd packed above the c(2 x 2) alloy. EAM calculations confirm the stability of this model. Evidence from MEIS and TDS, however, shows that the monolayer surface as prepared in this work is inhomogeneous. c(2 x 2) and Cu rich surface domains exist in addition to those having the p4g Pd/d(2 x 2) PdCu structure.

Surface Science, 337, 79-91, 1995.


Phonon spectra and mean square displacements on Cu(11n) vicinal surfaces

Surface phonon spectra on Cu(11n) vicinal surfaces, with odd number n = 1 to 19, are studied by using the continued fraction method and embedded atom potentials. Vibration frequencies for atoms at step edges are found to be softer along the surface normal and the step normal directions than those of terrace atoms and bulk atoms. Stiff frequencies along the surface normal direction are found for those atoms (with bulk nearest neighbors) located just beneath the step atoms. We find the surface relaxation induces 10-35% stiffening in the force constants of stepped surface atoms. The mean-square displacements (MSD) for atoms at vicinal surfaces are calculated at different temperatures. The surface MSD is found to be isotropic for the (100) surface and anisotropic for the Cu(11n) surfaces.

Surface Science, 303, 395-408, 1994.


Dynamics of a metal overlayer on metallic substrates - high temperature effects

We have explored the structure and the dynamics of a bimetallic system consisting of a hexagonal (almost) overlayer of Ag on a square lattice (Ni(100) and Cu(100)), as a function of the surface temperature. In each case the structure is "nearly" incommensurate giving rise to a low frequency Goldstone mode. Also, the overlayer atoms slosh back and forth over the substrate in a corrugated fashion. The calculated dispersion of the Ag/metal vertical mode, at room temperature, is in excellent agreement with experimental data. At higher temperatures floater atoms appear on top of the overlayer displaying a variety of cluster formations and also exchanges with the substrate atoms leading to surface disordering, interdiffusions and melting.

Mat. Res. Soc. Symp. Proc., 291, 205-10, 1993.


Complicated Exchange-Mediated Diffusion Mechanisms in and on a Cu(100) Substrate at High Temperatures

We present results obtained from a molecular dynamics study of the behavior of isolated copper atoms placed on a copper substrate. The atomic interactions are modeled by the embedded atom method. At 900 K we find that diffusion frequently proceeds by a two-step exchange-mediated process. In the first step of the process an isolated surface atom enters the Cu(100) substrate creating a strain along a close-packed row. In the second step the strain is relieved by an atom in the strained row returning to the surface of the Cu(100) substrate. The atom which returns to the surface may be several atoms removed from the atom which entered the substrate.

Physical Review Letters, 71, 2445-8, 1993.


A Spring Study (1994) of nocturnal migration of passerines using acoustic microphones

In the Spring of 1994, acoustic microphones were operated at Long Point and St. David's in southern Ontario. The microphones were operated for 8 hours each night, starting at 8:00 pm EST, and their output recorded on a VCR. The VHS cassettes obtained were then listened to, and the number of night migrant contact notes or "chips" was recorded for 10 minutes in each half hour. No attempt was made to identify each chip, but the chips were divided into warblers/sparrows, thrushes and others. This report presents the results of these chip counts.

Physics Report, PR-1994-2.


Palladium Atoms on a Copper surface: A molecular dynamics study

Atoms are known to move rapidly on metal surfaces. At the present time it is not possible to study these motions experimentally. It is possible, however, to study the motions theoretically using a technique called molecular dynamics. In this paper we illustrate the technique for palladium atoms placed on a copper surface. Experiments at room temperature have shown that the Pd and Cu atoms form an ordered structure when a Cu surface is exposed to a Pd gas. Using molecular dynamics we have searched for the atom movements which are the origins of this ordered structure. Under certain conditions we find the deposited Pd atoms and substrate Cu atoms change places. The nature of these Pd-Cu exchange events and other motions of the Cu and Pd atoms on the copper substrate are examined. We also present the results of a study of the bombardment of the Cu surface by Pd atoms.

Comments Condensed Matter Physics, 16, No.5, 281-305, 1993.


Dynamics of a Ag overlayer on Ni(100)

We have examined the structure and the dynamics of a nearly incommensurate monolayer of Ag on Ni(100) for a large range of temperatures using molecular-dynamics simulations based on potentials from the embedded-atom method. On the average surface the structure is a nearly hexagonal c(2 x 2) as expected from previous experimental data. At 300 K we find the Ag overlayer to slide back and forth in the nearly incommensurate direction on the Ni substrate while the vertical height of the silver atom vascillates between a lower value (~2 A) at the hollow sites and a slightly higher value (~2.4 A) at the bridge sites. There exists also a low gap frequency (Goldstone-like mode) for displacement parallel to the nearly incommensurate directions along which seven Ag atoms are accommodated in the spacing of eight Ni substrate atoms. At this temperature the calculated dispersion of the Ag mode polarized perpendicular to the surface is in excellent agreement with experimental data obtained from inelastic electron scattering. Between 1200 and 1600 K the increased (and anisotropic) mean-square vibrational amplitudes of the atoms lead systematically to the creation of vacancies and floater atoms, to clustering and unclustering, to surface disordering, and eventually to melting. The behavior of the Ni surface with the Ag overlayer is strikingly different from the bottom Ni surface with no such overlayer.

Physical Review B, 48, 5530, 1993.


Ultrathin Pd films on Cu(100): An investigation using the Finnis-Sinclair potentials of Rafii-Tabar and Sutton

The energy per atom of various surface configurations, when a half monolayer of Pd is deposited on Cu(100), is calculated by using the Finnis-Sinclair potentials of Rafii-Tabar and Sutton. Long-range order in the alloyed Cu/Pd surface is also calculated as a function of temperature. The results of the energy calculations are in agreement with existing experimental observations, while the results for the long-range-order calculations suggest that future experimental data may exhibit two transition temperatures.

Physical Review B, 46, 4292-4, 1992.


Structure and dynamics of an Ag overlayer on Cu(100): a study using the embedded atom method

Abstract

We present the results obtained from molecular dynamics simulations of an overlayer of Ag on Cu(100) using potentials from the embedded atom method. As in the case of an Ag overlayer on Ni(100), the overlayer slides back and forth on the substrate along the nearly incommensurate direction. The mean square vibrational amplitudes of the Ag atoms are also largest along this direction. The Goldstone mode has a frequency of 1.3 cm-1 at 300 K. At higher temperatures the surface disorders and Ag and Cu atoms interdiffuse. The dispersion of the lowest frequency vertical mode is in good agreement with inelastic electron scattering data. We also present some explanations of the phonons at T and the structure factor of the system.

Surface Science, 291, 215-25, 1993.