Introduction Highlights

Waterfowl and man has been connected for thousands of years. And how do we maintain this connection with waterfowl currently? Tragedies of over hunting and near extinction for many waterfowl species occurred during the 20th century. Hunters recognized with continued intensive hunting, many waterfowl would be depleted and therefore the sport they love, the animals they love would disappear. So they decided they had to put their foot down and learn how to manage these waterfowl populations sustainability.

Waterfowl and wetlands 
Waterfowl refuges were created, the duck stamp was indited, and the hunters awareness of the populations numbers increased. Duck Stamp created revenue for these refuges in order to protect not only waterfowl, but many other species. Through hunting taxes, many ecosystems have been able to be preserved. However, now that the waterfowl populations are increasing, the hunters who provide currency to protect them are decreasing. How will we protect our species when there is no longer money coming in? By chance charging extra taxes on binoculars, entrance to parks and memorials will help pick up the lack of income from the declining hunter population. Hopefully it is sufficient enough to protect our ecosystems.

Janet Kear wrote a book entitled Man and Wildfowl. However, it was too expensive for me to purchase, but I found a book called Wildfowl and the text was written by Janet Kear. In this book, she had a chapter called Wildfowl and People.
Geese have been domesticated as early as 5000 years ago, beginning with the Greylag Goose (Anser anser) and shortly following the Mallard, Swan Goose, and Muscovy Duck. Their domestication was associated with utilitarian purposes: pets, food, and feathers. A hypothesis about the beginning times of agricultural conflicts with geese begins with the Greylag Goose (grainivores and therefore potentially had conflict with raiding croplands) which is interesting since it is one of the first domesticated geese, per chance due to the conflict. Also, an interesting fact is the difference between white and dark domestic ducks. White forms of waterfowl are typically weaker and picked off in the wild; however, the white geese grow quicker. Dark forms typically take longer to grow, however, they lay eggs for longer periods of time. Therefore, upon domestication, white geese are used for meat and dark forms are used for eggs.
In the current day, humans and wildfowl are getting closer, causing disturbances on both parts. Pink-footed Geese consume carrots in Iceland, Magpie Geese consume rice but humans, too, have an impact on the animals (you can see some of these man-made conflicts in the Population Dynamic section).

Feeding Highlights

A waterfowl managers only job is to see if the waterfowl are feeding well. Interesting! When I was thinking of coming up with a field project, I was trying to decipher why the information I would be gathering about diving physiology would be significant. Well, this is why. A huge majority of the waterfowl managers job is to ensure that the waterfowl are feeding well. That is their job, and therefore they need scientific backing in order to be certain their waterfowl are feeding well!

Adaptive radiation is something that I am having problems with. From my point of view, I see it as certain animals living in a given environment. In this environment, there are certain things that are preferred over one another. Since there is a lot of competition, however, the animals must find secondary resources to forage on. Therefore, in a given environment animals that would normally compete and maybe run the other into extinction, instead they eat food they wouldn't want as a first choice, but it will permit them to survive. Throughout time of choosing this secondary resource, this animal becomes more specialized to eat the secondary resource and by chance it can become a primary resource through many evolutionary years. There was an interesting example from "What is evolution? Darwin's brilliant idea." One of the exercises was to forage as much "wigglies" as possible from a "tree top" in a given time, however, some of the students had  a mutation. A girl had the mutation of kneeling and foraged more than most. Although, this seemed like it would be a disadvantage, since the other people were grabbing the food from the "tree top" many of the "wigglies" fell and she was able to gather the "wigglies." The mutation was favored for which means natural selection, which is dependent on the environment (i.e. foraging sufficient "wigglies" from tree tops) will favor those mutations in which was capable of adapting to the environment.

How have these animals adapted to foraging? How did favorable mutations that we see in current waterfowl begin? What restrains were imposed on the waterfowl to create a new adaption?

Exploitation of habitats:

Different ways of exploiting habitats:

Swans typically feed by grazing on submerged vegetation, putting their tail end in the air and extending their necks as far down as possible

Geese usually feed in the day. Some of the grazing species must eat for the majority of sunlight hours.  Some geese are even known to "farm" their foods by feeding on one plot and then moving to the another one to allow the plots to grow by just lightly grazing on the plants.

Dabbling ducks are easily spotted in Arcata Marsh, all you have to do is look for a rump sticking up in the air, and you have found a dabbling duck. Many of these ducks will often eat diurnally as well as nocturnally. Some even primarily feed at night, much different than the geese we saw previously. Due to the foraging technique, these dabbling ducks can usually only feed in shallow waters and marshy wetlands by filtering through the water. They use certain techniques to filter through the waters to find the highest densities of seeds an invertebrates since they cannot actually see these in the waters. 

Diving ducks are also easily seen at the Arcata Marsh. If you are looking at a waterfowl species and it magically disappears under the water for a few seconds, you have found a diving duck! Diving ducks are usually always nocturnal. For example, I am studying the Ruddy Duck and I have read many papers saying that it is hard to study the foraging behavior of Ruddy Ducks due to the fact that they feed during the night. In my study, I mainly see the ducks sleeping rather than eating, because they sleep in the day and forage during the night.  

Food selection:

These two graphs show the types of selection that North American Ducks do including plant and animal material! This can show us the difference in mainly vegetarian or mainly animal consumers.
An experiment done to see the different types of food selections within an already preferred food group (mussels) was done with the Tufted Duck. It found that when given the choice, Tufted Ducks often times ate smaller mussels than the larger ones. This is could be because it could be more profitable to collect and eat two small mussels with the same time it would take to collect and eat one large mussel. This most often happened when there was high densities of mussels. When there were lower densities of mussels, they preferred the larger mussels versus the smaller mussels.

Eider ducks being fed. It's amazing to see all of the energy and effort diving ducks must do in order to get the food at the bottom of the water. Female eider is completely endogenous

The Barnacle Geese are very picky when choosing where to forage. They expend a lot of energy in order to forage, so they must ensure that the are getting a sufficient amount of nutrients for the amount of time spent in foraging. And they select the most nutritious part of the plant, the younger and large leaves and peck at very high rates.

Genetics of large geese are basically in all barnacle geese. Bigger geese are the only ones that are reproductively successful, so that is what the genes are in every goose! However, it is the food that the geese receive in their first months of life which determine their size. When seeing a small goose, it is actually just because of the environment they grew up in. Either there was severe weather, unsuitable habitat among other things. Once these geese are of mature age, they will no longer change. 

It was found that the presence of foxes on the breeding grounds prevented feeding. When the fox were present, the geese tended to stay in closer packs to avoid predation. When the foxes were removed, the geese then spread out into land they did not explore previously due to the risk of predation.
Males chase away others while females are foraging, in a way protecting their little patch of vegetation.

Breeding Biology

Pair formation

So what starts off this expedition to an amazing nesting site? Dedicating a life to their ducklings? Well it begins with pair formation. Males ducks become very showy in order to entice the female onlooker while the female remains drab for optimal camouflage in order to protect the nesting site. The primary reason why males are so showy in ducks is because they are polygamous, meaning one male will obtain many females either during a mating season or at least in his life time. This means that they must look as fit as possible to obtain the females, they are in constant competition to get the ladies. However, the larger counterparts of the waterfowl world, geese and swans are not sexually dimorphic and therefore many of them are monogamous for life. This means they do not need to spend a lot of energy to seduce the females ducks into mating. The showy Bufflehead is one of the only ducks that breaks the trend of polygamy and will mate with the same female for many seasons (Check out more about the Bufflhead lifestyle, check the other blog post about Bufflheads).

During the breeding season, females greatly benefit from pair formation. The male will usually watch out for predators and defend territories so that their females can get optimal food reserves. For male ducks, at least, the breeding season is costly to them due to the fact they must upkeep their showy plumage.

This is a ruddy duck penis is in the shape of a crockscrew and is one of the largest in the animal world. The bar is 2cm for scale. This video shows the erupting penis from a  Muscovy Duck (Cairina moschata).  It was mentioned in this book: The Dawn of the Deed by John Long. He said that the the Muscovy duck is able to erupt it's penis within 0.4 seconds.


Time to nest
The best time to nest is when food is at the highest point. For example, the Laysan duck of Hawaii needs to ensure that it's ducklings will have sufficient amount of food when they hatch. So they do this in correlation with the brine flies.
Correlation of abundance of Brine Flies and nesting season
Breeding range 
Birds typically attempt to breed as far north as possible where there is plentiful food. However, with larger waterfowl populations, the less competitive species breed at lower latitudes. The preferential thing to do is to breed close to wintering grounds in order to minimize risky journey while migrating.

In class, we discussed as a group what we would do to create the most beneficial nesting site for ducks, or a duck in particular. So when we want to think of the placement of nest, what are things we should take into consideration?

• Will the nest site flood?
• Is the nest cryptic enough?
• Potential predation?

• Do they nest in the rocks...cavities...trees?

• Are the females endogenous or exogenous? Will she need to travel to find food?
• How densely packed are the nests?

We decided to choose the wood duck and created a sketch of what we thought would be most appropriate for the wood duck:

Egg and clutch size

If you view Element 1, you will see the wide range in clutch sizes. Ruddy ducks, for example, will lay eggs throughout the incubation time larger in mass than themselves. Although the rule goes, the larger an egg is in relation to body size, generally the clutch will be smaller.

Incubation

Female birds have a brood patch. This means they pluck away down in order to display a bares kin spot. With this patch, they lay on the eggs and warm them with close body contact to the eggs. For ducks, many males do not help the female with incubation. Geese and swans, however, will share the responsibility by the males guarding the territory and the female incubating. Emperor Geese are the most loyal egg layer, staying with the nest for 99.5% of the incubation period.

Renesting
Swans and geese do not renest. However, ducks do so long as the renesting occurs early enough in the incubation period. The environment in which ducks live in is hardly in favor of their nest surviving. Usually the older birds renest because they tend to be more fit and begin nesting earlier than the younger ducks.
Hatching and rearing
The most amazing thing I read about waterfowl thus far is the unhatched offspring, will begin to make calls to the outside world to their parents in order to synchronize hatching two days before hatching.






Growth & Development of young

Ducks are fortunate because there is so much energy put into the egg, that as soon as the egg hatches, within a few hours the ducklings are fluffed up and ready to walk. Ready to feed themselves, eyes open, waddling little bodies into the dangerous world. The main responsibility the mother has is protection. Once out of the nest, the world is a scarier place, with the protection of mom from predators or interspecfic competition, the ducklings are much safer.
Here's an interesting little story about a mother duck saving her duckling from seagull predation.



The main things I gathered from the Barnacle Goose breeding biology is they choose their mate according to:

1. Size of partner
2. Age of partner
3. Region the partner was from

But mainly, these three criteria were selected for  more frequently if it was similar between the mating pair. Similar age, natal site, and size of partner resulted in the most pairs. 

Also, it seemed as though younger geese attempt to mate, but they rarely do so successful. From my own opinion, I hypothesize that even though they most likely won't be able to do it, yet they still put energy reserves in it, I hypothesize that it is due to gaining more practice and experience at tending to young. I derive these predictions from the fact that once there is too much energy that needs to be invested in young, the Barnacle Geese will usually abandon a nest or goslings when it is too difficult. If they invest all of their time into a clutch that will most likely not survive, then they are potentially going to lose the chance to reproduce successfully in the future. Say, they stay on their nest too long to incubate and there is no food around, they will lose valuable nutrients for a clutch that was not going to survive anyways due to lack of experience. They abandon the nest when it becomes to energetically demanding and when there is a loss of experience gained. Only 17% of the population ever reproduce successfully anyhow. 

Sexual and Social Biology

Mating systems
Waterfowl have a more complex mating system then we give them credit for. Many believe all waterfowl are monogamous and remain with one partner for their lifetime, however, that is not the case.  Some are seasonally monogamous, some are life time monogamous some are always polygamous, but there is a gradient. Completely monogamous consists of geese and swans and Buffleheads. Ducks are, for the most part, seasonally monogamous. Completely polygamous includes the Magpie Goose.  The interesting thing about Magpie Geese, however, is they breed cooperatively. Generally a male has two females laying eggs in one nest that all three geese built.  This paper found that when the Magpie Geese are in pairs they have about 8 eggs per clutch and about 9 when they are a trio.
A fascinating topic of birds is nest parasitites. We all know about the classic Wood Duck example, she will find any nest box or cavity, and lay her eggs in them and leave. She is not an obligate parasite, and she parasitizes within her own species, but she is a parasite nonetheless. The Black-headed Duck is an obligatory nest parasite. They have never once touched their offspring and allow other animals such as Coots to take care of their young. Redheads will parasitize on the Canvasback, which is peculiar since the Redhead is smaller than the Canvasback.








Family behavior
The size of a group effects the success of encounters with individuals of the same species. A study on the White-fronted Goose, done back in the 50's found out that paired geese beat single geese and when it came down to the family size, the larger the better in aggressive encounters. In the late 80's a study was done with Barnacle Geese and it was determined that the bigger the group size (much like the previous study), the better the chances of the geese success, regardless of age or weight. In the end, it makes sense that the family sticks together to create a more secure future for their fledglings.
Territoriality

Usually ducks aren't particularly territorial like geese and swans, however, the Northern Shoveler is an exception. Also, the female Barrow's Goldeneye is extremely defensive. As seen in the documentary Tough Ducks, the female Goldeneye will often times fight other females even if they are not conspecifics in order to keep the other ducklings and females away from territory. She will even kill ducklings of the other brace to send a message.
Flock behavior
What is the benefit of gathering in flocks? For one, this could be a higher competition factor for finding food as well as roosting sites. Although, it can provide some benefit such as anti predator tactics.
Interspecific competition
Steamer Ducks (Tachyeres brachypterus) have been noted to be extremely territorial Often times killing their unwilling opponent in order to show their stamina to the female.



Barnacle Geese are very monogamous, more so than most birds. This may be attributed to the fact that they have high mate guarding. However, sometimes there is an egg in the nest that does not belong to the father. Is this extra pair paternity? No, it does not belong to the mother either. Barnacle Geese will sometimes nest parasitize on conspecifics. Although the mating pair that is on the nest being parastizied views this occur, they still take on the egg and will even take care of it. This is per change due to an egg being on the outside will cause predators to go to the nest to gather the eggs and potentially other eggs. So the mother scoots the egg into her nest to avoid this risk. Also, when geese have larger family units, they will usually be more successful because the goslings are able to follow the parents to the wintering grounds and defend territories. More bodies, the higher they are on the social ranking.

Population Dynamics

The nature of populations
Understanding population dynamics can help us understand the conservation of species. Some populations are sedentary, some populations migrate, some populations have bottle-necking  and some populations are far too large and need to be managed for control of size. Populations vary, in sum.
Monitoring techniques
NAWMP page demonstrates that there are people hard at work to measure populations of waterfowl in North America for optimal harvest rates by using airplanes to obtain large scale counts of migrating waterfowl. And from harvest rates, we can also know the amount of deaths per species per year for species able to be hunted.
Age of first breeding

Element 1 describes various ages of first breeding for birds across the expanse of the waterfowl groups. A general trend was diving ducks and geese was about 2 years and dabbling ducks breed at about one year.
Nest success 
Different types of nest habitats can effect the success of individual nests. For example, if one nests close to water, they are at higher risk for flooding. If one nests with mammals, they are more at risk for predation. Also, food has a huge factor on if an animal will be successful or not. For example, the Barnacle Goose had a very small success rate (21%) when little vegetation was present, but when there was high vegetation they had a much higher success rate (84%).
Survival from hatching to flegding
Due to the large yolk sacs that the eggs of waterfowl contain, some of the birds can last many days without food because they have enough reserves to tie them over, so starvation isn't too much of an issue. Predation of ducklings and  gooslings is an issue for survival. Luckily for the Swans (Cygnus) they are able to defend their young quite well due to their large size.
Post-flegding survival
How successful a parent was can really be determined by post-fledging survival. However, finding the hard data behind this is extremely time consuming and expensive. So we usually just use the fact that a bird fledged to be an indicator of success since other indicators are difficult to quantify. 
 Mortality- Main causes of natural mortality are 1) Disease, 2) Predation, 3) Starvation (the number one cause). Man-made mortality counts for the majority of mortality of waterfowl.
Disease
During class discussion, a classmate discussed Cholera in waterfowl. She said in her paper it found that higher levels of phosphorous triggered this bacterial outbreak which would in turn lead to Cholera. What could managers do about this to prevent future issues of Cholera outbreaks?  
Man-induced mortality
During discussion, a classmate had a paper that talked about harvest of waterfowl. Our papers were very similar so we discussed a little further to try and clear up our understanding of harvesting and its effect on waterfowl populations. In her paper, they proposed that harvest could help decrease the density of waterfowl populations and therefore survivorship would actually increase because there is not so much density. Upon hearing that, I create a hypothesis of why that could be: since there is less competition two waterfowl of equal fitness do not have to compete for food when the entire food source is vital for one of the birds. Therefore if one of those animals dies, the other is able to survive. Starvation is the reason for the most natural causes of death. My paper stated that harvest was additive which follows Jess' paper.
Mortality in relation to age and sex
A very interesting example of mortality in relation to age and sex was the Mute Swan's deaths of overhead wire collisions. It was found that the majority of swans killed were 2 year old. Why? The reason proposed is these swans are more frequently distributing to find their territories and therefore are more likely to collide with these wires.


The control of numbers

Compensatory mortality versus additive mortality. I have struggled a lot with this concept because I am not sure which one is right. Some of the literature says that our current state of harvest and some say it is compensatory. What is compensatory and additive harvest, exactly? Compensatory harvest is basically saying that the waterfowl taken from the natural world is done in a way that does not add anymore deaths then would be naturally taken. Additive, however, basically says animals that harvest increases the amount of deaths that would be normal for the natural world. It was kind of what I was talking about in two sections up: man-induced mortality.




The Barnacle Geese populations are increasing; however, due to their still small population size (under 125,000) these geese are not hunted. The most important thing that was found in the population growth was having proportion of successful breeding pairs in the population. This means that when the population starts to do bad, the first thing we should focus on the proportion of successful breeding pairs in the population. This parameter was not density-dependent. Rather the proportion of successful breeding pairs depended on snow and ice as well as the presence of foxes.