Our Waterbirds have died off is West Nile Virus the only cause of their demise, could there be a different cause?

  I spend a lot of time outside, mostly looking around and watching the birds, animals, and anything else that moves within my eyesight. I have my binoculars, and video camera, I use my cell phone for pictures some of the time, but I prefer a camera. I suppose it has to do with my age, or perhaps just not liking to take photos on a telephone. I must admit I just got an upgrade, to a Samsung 9, good grief I didn't care too much for my old one, I didn't want a new phone but my wife's crapped out and it was cheaper to upgrade both of them. I take pictures of the animals, birds, and boats passing by, actually I'm still learning how to take good videos if you watch one feel free to tell me what you think. (Link to my video)

Beautiful bird, loud and numerous, Red-Wing Blackbirds

  I miss the animals this year, they have been dwindling down for the past few years, the first I noticed was the Red-Wing Blackbirds. There is an island about 1/4 mile from me where the blackbirds were very populated, until 5 years ago. They started to thin out, it wasn't noticeable at first during the fall when they usually left for the winter. Normally I don't pay much attention to them leaving, it's the returning that I am tuned into more often than not. One year, about 3 years ago, none returned, not a single one came back to bird island. In fact, I was talking to a person that lives near the island and she referred to it as "Grass Island". I told her it was at one time known as "Bird Island", she asked me why, so I told her. (they have not lived in that house very long) After the Red-Wing Blackbirds abandoned us, they were followed by the Mudhens. It's the same situation at one time about 3 years ago on the slough hundreds of Coots lived in an unorganized flying army. The Mudhens are very entertaining, I would watch them for hours some mornings, their activities looked like a choreographed dance presentation. The Geese, Mallards, most Ducks, and the Crows all followed. So what has caused the disappearance, thinning, or abandonment?
  West Nile Virus (Link to a paper on WNV) is mentioned most of the time as the suspected fly in the ointment. We know humans are capable of contracting the illness from mosquitos that have come into contact with an infected animal. Passing the disease to humans, it is unnoticed by 8 of 10 who are infected by it, that's the 80/20 rule in motion, 80% display no symptoms. One person of 150 who are infected develop serious diseases such as encephalitis, (This is an infection of the brain). Meningitis, inflammation of the fluids and membranes surrounding the brain and spinal cord.

   I've listed four symptoms of a severe illness caused by the West-Nile Virus:

  1) High fever, headache, stiff neck, stupor, confusion, disorientation, coma, tremors, convulsions, weak muscles, diminished vision, numbness, and paralysis.

  2) The disease affects anyone, elderly persons over the age of 60 are in a higher risk group, especially if suffering from cancer, diabetes, high blood pressure, kidney disease, or have been a recipient of an organ transplant. Anyone with any of these diseases is higher risk.

  3) It takes weeks or month's to recover, some damage to the nervous system may be permanent.

  4) One of 10 of us that develope a severe case of West Nile Virus affecting the nervous system, die.

Crows are everywhere, but some areas have lost populations due
to the West-Nile virus.

  It's a virus infection detectible through medical tests, be certain to seek medical help if you suspect West-Nile Virus infection and are suffering any of the above symptoms. We hear about a few people contracting the disease every year, and we do find some of them are hospitalized, and some do in fact pass.

  How does that affect the birds? The disease has been discovered in birds, Crows and Blue Jays are known to contract the disease, get extremely ill and die. In my area we can report dead birds to the County Health Department, the bird will be picked up and examined for cause of death. Many of the most successful detection programs depend on the local citizens to report dead birds, it's a program that works. West Nile Virus is transmitted to birds when bitten by Mosquitoes, who in turn are infected when they make a withdrawal from an infected bird. Scavengers (Crows, and Turkey Vultures) may become infected after consuming a diseased animal, predators (Owls, and Hawks) may come in contact with diseased prey, or scavenging. West-Nile Virus has been detected in over 300 different species of birds, most birds do survive, Crows and Jays most frequently die of the disease. The disease was first discovered in North America 16 years ago, birds are the viruses main host, unfortunately, North American species had never encountered the disease prior. The bird virus has had free reign, it spread across the continent in just 5 years killing millions of birds in its path, climate and habitat affect how the birds respond to the pathogen.

Even this guy is not immune to West-Nile Virus

During the year of 1999, a team of scientists began checking birds at the Monitoring Avian Productivity and Survivorship (MAPS) stations for West-Nile Virus. They studied 49 species in 14 Avian families adults to accurately determine the number of survivors. The study revealed twenty-three of the species, 47% of those studied, were negatively affected by the virus. Some Species, the Red-Eyed Vireo had a population drop of 29% when they first encountered the disease, approximately 37 million birds died as the results of being severely infected. The population was estimated at 130 million members, amazingly they suffered a massive die-off during the first year of exposure only, then they recovered, a pattern scientists expect to be repeated. Like humans during a flu outbreak, the birds seem to have built up an immunity, causing the impact of the disease to lessen.
  On the other end of the spectrum the Warbling-Vireos dropped a mere 8.7% in the first year they were exposed, but they have not recovered. The 8.7% decline continues to this day, year after year compounding the effect of West-Nile Virus. The original population was 49 million Warbling-Vireos, the virus has so far killed 15 million birds.
  Some birds are more adept at dealing with the disease, the Spotted Towhee, and song sparrow suffers no ill effects, it may be because they have more food resources, bird feeders for one. It's not a broad brush, 11 other birds in Urban areas lost a lot of their population and continue to lose. The Chickadee, American Robin, and the House Wren were unaffected by the virus and continued to thrive while it is all around them. It is not known why some species do better against the disease than others, it will take a substantial amount of study yet to be performed.
  North Dakota performed a study of the Red Wing Blackbirds, they found 22% of the tested birds carried WNV (2003) and 18.3% (2004). Resulting in discovering that the Red-Winged Blackbird migratory populations were instrumental in spreading the disease throughout the continent, with no end in sight. Mudhens (American Coot) have been found to be a "sentinel species, indicating the presence of the virus in ponds and the wetland environments. Hopefully, the birds will build up an immunity, it is my observance that in our area the population is on the upswing, that also may be wishful thinking or hoping.

Warbling-Vireos

   A recent study performed by Lund University in Sweden have mapped the origins of migratory birds. It was done to investigate the differences in the immune systems of migratory birds as compared to sedentary ones. The conclusion is that migratory birds are at an advantage when it comes time to raise their young, they leave the tropics and head North which gives their young a better chance of survival. The young birds have a weak immune system, leaving them exposed to the many viruses and bacterias that thrive in the warm moist tropic environment. It says nothing about the possibility that the adults carry the virus North with them, apparently, if the virus is able to infect Red-Wing Blackbirds in North Dakota allowing them to spread the disease Nationwide, It seems logical any bird exposed anywhere in the world is able to become a carrier as well, I'm not sure if we can assume it's a universal occurrence.
  It makes me wonder if at least part of the reason our local bird population is dwindling is partly West Nile Virus and (wishful thinking probably) the birds' realization that WNV is rooted deeply in some areas, avoiding our slough as suggested in the Lund study.  California and Texas are two of the hardest hit by the virus, I do hope that the scientist is correct in that the birds will build up an immunity. I was told the same story years ago when the H1N1 bird flu was going around here, I got immunized. I also got the bird flu, my doctors' comment was "well, sometimes it happens". when I got it the second time two months later she said "well, this never happens", I thought it was pretty funny after the flu passed.
  Yes, the Crows, Bluebirds, Coots, Red-Wing Blackbirds, Bluejays and Ducks are all suffering from exposure to the disease. Some of the birds appear to be recovering, others I am hoping are using their instincts and are avoiding this area due to the disease, as studied by Lund University, however that may be wishful, we will find out. (follow this Link to a paper on the Lund study)
  Thank you for reading and sharing my blog, the disease at some point will run its course, perhaps it will be a recurring event like the flu that sweeps the human population every year or so. Seek medical care if you experience any of the symptoms, if you are in an area of recent flooding and you have a weak immune system, be especially observant, do not hesitate to seek medical care.
jacquesandkate  EmergencyKitsPlus.com