In a study conducted by Daniel Twedt, Paul Hamel and Mark Woodrey, they compared two different survey methods for determining species richness as well as relative abundance of grassland bird populations.  Their study area included 23 different sites, 9 coastal pine savannas and 14 recently reforested areas.  The study is titled Winter Bird Population Studies and Project Prairie Birds for Surveying Grassland Birds.  The study compared two survey methods, the first called Winter Bird Population Studies, is a method which has been used for decades, which simply involves a single observer to methodically move through a search area and identify and count all birds detected.  The second method titled Project Prairie Birds involves three researchers, the observer and the two “flushers”, it was designed to better determine the population and abundance of secretive species.  The study found that the Winter Bird Population Study method tended to overestimate the species richness.  While the Project Prairie Bird tended to overestimate avian abundance.  They also concluded that both of these methods are ineffective and suggests that the use of distance-based survey methods would provide the most complete results.

A study by David Watson evaluates the effectiveness of different survey methods for birds.  Titled Comparative Evaluation of New Approaches to Survey Birds, it focuses comparing new methods to survey avifauna diversity.

In the study he compares two emerging methods, which he himself devised for measuring bird diversity, and two methods that are used widely in the field today by Australian Ornithologists or Ecologists. To determine which method was the most successful he compared the results of the tests to the discrete count; or the actual richness. He analyzed the benefits and the drawbacks of sac method as well.  He conducted the study on four different preserve plots in grassy box woodlands in areas of Albury and New South Wales.  The plots which were chosen were varied in size so as to best determine if a specific method is better suited to a specific sized plot.

David found that of the four sampling methods his new method of strict standardized search yielded the most complete results of 78.4 percent completeness. This method involved 20 minutes searches, and after three consecutive searches yielded no new species  you were to stop sampling.  Another stopped rule was applied to his second new method, which although its completeness was only 72.5 percent, it took half the time of the strict standardized search making it much more efficient.  Lenient standardized search stopping rule was simply stop when the number of species seen in a single sample period were equal to the species seen in two sampling periods.

Compared two the two older methods of repeat transect and time-balanced area-proportionate transects the two standardized methods were clearly the better methods.  Repeat transect only producing 33.8 percent completion, which the TBAPT produced only 37.1 percent competition.  So all in all his new survey methods were much more effective at determining the diversity of the avifauna of the preserves than were the methods in use by most ornithologists in 2004.

An article written buy Thomas Howell and George Bartholomew, who is the #1 fancy man, is titled Temperature Regulation in the Red-Tailed Tropic Bird, and the Red-Footed Booby.  It was published in 1962 and is a study of temperature regulation of nesting seabirds and their hatchlings.  The study took place on Midway Island during June and July of 1959 and 1960.  They measured the temperature of the egg’s internal temperature, by drilling a small hole in and inserting a device to measure the temperature near the center of the egg.  They also measured the surface temperature of both adult and hatchling, as well as the foot temperature of the adults.  Foot temperature, seems an odd thing to measure, but the Red-Footed Boobies lack an incubation patch which helps heat the eggs during incubation.  Instead the boobies cover the egg with a portion of their feet, so to determine the effect on incubation, foot temperature was measured by the study. They found that the food temperature was no higher than with seabirds that had an incubation patch, but that the use of them none the less contributed to the temperature regulation of the egg.  Other than feet temperatures they also collected deep core temperatures, which were sampled by ‘gently inserting a steel-sheathed or vinyl-sheathed thermister probe down the esophagus to or into the stomach’, of awake birds, captured by hand.  One of the findings of the study was the there was no correlation between the deveopmental stage of the eggand the internal temperature.  They also found that adult and hatchling cooled themselves mainly through evaporative cooling as well as through panting and their feet.

Severity of the Effects of Invasive Rats on Seabirds A Global Review, was published in Conservation Biology, by Tershy, Croll, Keitt, Finkelstein and Howald.  It is a combination of many different case studies of invasive rats and their effects of seabird populations. Ninety-four different case studies of 115 different rat and seabird interactions on 61 different islands were used . It used these studies to determine which species of invasive rat was the most harmful to seabird populations. They found that the common black rat, or ratus ratus was the most harmful.  They also looked at different characteristics in birds that made them more or less susceptible to being effected by invasive rats.  These characteristics included things like size and breeding behavior as well as life history traits like whether they were ground nesters or burrowers.  They found that smaller burrowing seabirds were the most susceptible to invasive rat species.  This study also outlines the bird families which further study would be most helpful  in determining the effect of invasive rat species.  They used a data analysis method which i was unfamiliar with called meta-data analysis. This article was very useful for me because it provided me with a good deal of case study literature in the bibliography for me to search through.

Gregory Hendricks

The article titled Eradication of black rats Rattus Rattus from Anacapa Island written by Gregg Howald, Josh Donlan, Kate Faulkner, Steve Ortega, Holly Gellerman, Donald Croll, and Bernie Tershy studied the removal of an invasive species of rats from an island ecosystem.  Anacapa island is an  island off the coast of California in the California Channel Island chain east of Santa Cruz Island and north of Catalina. Their method of eradication was to disperse a rodenticide aerially staggered over 2 years.  The rodenticide they used was  brodifacoum, an anticoagulant which was incorporated into bait which they dropped upon the island.  They monitored soil quality,  populations of birds, and of a native rodent to ensure that the soil quality and the native populations remained with an impact was mitigated.  The native population of rodents (deer mouse) were eradicated along with Rattus Rattus, but they were successfully reintroduced, and recovered to pre-eradication levels quickly. Their method of mitigation for the bird populations was to capture birds who were susceptible to poisoning, such as the raptors which fed upon the rats. They also tested the marine environment for impacts and found that there was no significant impact on marine life from the use of brodifacoum.  This eradication proved to be an example of the cost and effort needed to eradicate harmful invasive rodent species fromm island ecosystems. The project cost 1.8 million dollars and involved the heavy mitigation measures required to keep native populations safe.

An article which was published by The Condor, titled Effects of the 1982-83 El nino event on blue-footed and masked booby populations on Isla Daphne Major, Galapagos was written by Lisle Gibbs, Steven Latta and James Gibbs. They focus on the negative effects on the populations of these migratory birds created by the El Nino. These negative impacts include effects on the amount of available food, and reproduction.  The study included the measurement of three variables, “size of breeding populations, clutch size and degree of breeding synchrony, and the availability of nesting habitat for Blue footed Booby” (p440).  Oceanic disturbances like the El Nino have a large effect on the food supplies and breeding success of life such as the masked and blue footed boobies who rely on the ocean as their main source of food. Their method for determining the population of the blue and masked boobies was the count method.  Which is simply that they went to the various colonies of birds and counted the numbers of individual birds.  A bit of interesting information is that they determined the clutch size, brood size and the estimated age by simply looking at the plumage characteristic of the birds. They cite an auto named Nelson who provided the plumage characteristics.  The study found that there was a correlation between lower clutch sizes in years after the El Nino.

http://www.avibirds.com/pdf/M/Maskergent6.pdf

Greg H

Field Project 1: Finding Existing Data

Topic and Anticipated Research Question:

The dataset that I found included data on many species of migratory birds.  This data was the number of migratory birds recorded at various key junctions in their migrations, where the birds band together in large numbers.  This dataset could be used to analyze weather the populations of many North American migrants’ bird species are declining or growing.  You could also use the data to determine the effect of drought on the population of birds by locating data on the precipitation amounts in the summer breeding areas and comparing them to the recorded populations along the flyway from that year. The dataset that I choose is on the recorded count of the mallard because it is the most extensively studied migrant bird of North America and there was ample data provided.

Dataset:

1. 1.    What is it? The dataset is a list the number of migrant mallard ducks recorded at seven different key migration locations on the pacific flyway.
2. 2.    Who collected it? This dataset was collected by USGS, or the United States Geological survey
3. 3.    When was it collected? Data is available from 1960 when the first count began to 2013
4. 4.    Where is it available? This dataset is available at the United States Geological Survey website.
5. 5.    Form in which used? The dataset is available in an excel document format. Or displayed on a chart on the website.

Appropriate Dataset:

This data set is an appropriate dataset because it provides the recorded count of mallard populations traveling through the pacific flyway.  Additionally the it documents the past well and provides large amounts of data on past recorded populations making it ideal for a study of the growth or decline of the mallard population. So using this dataset one could very easily determine whether the population of mallards has been growing of has been in decline.

 Data Structure:

The data is structured by first choosing the bird in which you wish to find data. You then select the country and the flyway. From there the flyway is broken up into six or seven different points which funnel the migrant birds through mountain passes so as to get the most accurate population count. The data includes a chart provided by USGS or you can download the data in an excel format.

Data Extraction:

All you need to do to extract the data that you need is would be to determine which bird you would like to find data on, choose the flyway and the country and choose the years in which you are interested in.

Analysis Needed:

Simple charts and graph are all that are needed to display whether the population of mallards traveling through the pacific flyway is in decline or in a period of growth. A good way to show this would be through a line or bar graph by dissecting the data into its separate stages of migration, or creating a bar graph which compares the recorded number for each of the locations that they collect the bird counts.

To determine the what extent drought effects mallard populations one would have to run a regressions analysis of precipitation levels and recorded bird counts from the location. Maybe a multiple regression should be included and have other factors that like extremes in weather or temperature.

Greg H

Journal Exercise 2

Raymond Klaassen and Mikael Hake of Lund University performed a study of mortality in migrant birds.  It was published in the Journal of Animal Ecology in 2014 vol 83 pages 176-184 and titled “When and where does mortality occur in migratory birds? Direct evidence from long-term satellite tracking of raptors”.  Their study spanned over sixteen years of data collection.  To gather their data they affixed satellite transmitters; or banded 69 adult raptors, and found that mortality rate was six times greater during migration.  Most of these moralities were linked to particularly rigorous legs of their journey,  including the crossing of the Sahara desert in the Spring.   To determine the cause of the transmission loss several criteria were used, probable transmission failure, confirmed transmission failure, probable death, and confirmed death.  Using simple statistical analysis they calculated the survival rates by month as well as for breeding season, autumn migration, winter and spring migrations. The article does good work at showing its results in many different forms, including multiple types of charts and graphs, and even includes a map displaying the geographic distribution of the deaths.  While the study seems to point out an obvious conclusion of increased mortality during migration periods, it also sheds light on the  complexities of the death and migration of diurnal raptors. Their study found that the spring migration seemed to have a particularly strong effect on the annual survival rate of many of the diurnal raptors. This article was of particular interest to me because these researchers found a topic which many researchers simply glossed over, concluding that death was greatest during migration periods, but they delved into it and found interesting results.

http://0onlinelibrary.wiley.com.books.redlands.edu/doi/10.1111/1365-2656.12135/pdf

The article on “Carry-over effects from breeding modulate the annual cycle of a long distance migrant: An experimental demonstration” by Paulo Catry and his fellow researchers covers a facet of the life history of the Cory Shearwater.  It was published in the journal Ecology Vol. 94, No. 6, pp. 1230-1235. The facet of the migratory bird’s life history that the researchers examined is the effect of a failed breeding season upon the migratory birds, specifically their behavior, survival, and their subsequent geographic distribution. Paulo and his A team gathered data on this by removing the fledgling chick from the nest and banding the birds, thus synthesizing an unsuccessful breeding season in 2009. The A team then proceeded to band several pairs of successful adult shearwaters in 2009 to function as a control.  In
2010 the A team allowed the manipulated nesting pairs from 2009 to breed successfully to root out any unsavory concerns. The A team than simply placed the data upon a map, each bird supplying one data point, except the birds which were manipulated, which served as two in their successful and unsuccessful years. The A team toiled day in and day out to discover the hidden changes in behavior and geographic distribution between the successful and unsuccessful breeders. Well it didn’t take much toiling the data spoke for itself and a surprising 4/7 of the breeders which were unsuccessful chose to stay in the Canary channel rather than to proceed with the rest of the flock further south to the wintering grounds compared to the successful pairs of which 0/14 chose to stay.  The ever hopeful Cory’s Shearwaters that were manipulated/unsuccessful in their breeding season spent their time pampering themselves, molting early, and making sure they were in prime mating condition for the next breeding season in which they will surely excel. But perhaps the biggest finding of all was the fact that these unsuccessful pairs arrived to breeding grounds earlier than did the successful pairs, or their successful selves in the latter year. This is a great boon to their chances of passing on their genetics since many times a good territory is a source of great competition.