Rats suspected in the killings of Central Valley songbirds.

spectr17

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Rats suspected in the killings of Central Valley songbirds. The vermin are thought to be snacking on the birds' eggs in a forest preserve.

July 6, 2001, By EDIE LAU
Scripps-McClatchy Western Service


SACRAMENTO -- In one of the Central Valley's richest tracts of riparian forest, in a place seemingly safe for native wildlife, something is killing songbirds before they've even hatched.

Scientists trying to solve the whodunit in the Cosum nes River Preserve are using phony nests, cameras with infrared sensors and baited traps to catch the culprit. After two months of hunting, they've got a prime suspect, and they're not happy.

It's Rattus rattus.

Otherwise known as black rats, roof rats or ship rats, these are the critters that spread bubonic plague across medieval Europe. They're the ones who live in the trees of urban Sacramento, occasionally frightening people with their forays into yards and houses.

Adaptive, good at swimming, tree climbing and eating whatever's handy, black rats appear to be feasting on songbird eggs - at least, they've been caught time and again nosing in the fake nests, and their droppings are everywhere in the forest.

"Rats have been involved with extinction of birds throughout the world," said Andy Engilis, an ornithologist who has worked with the preserve since 1989.

What's most painful to guardians of the preserve is that songbird nests are being pillaged in a gorgeous cathedral of trees known as the Tall Forest, the biggest patch of valley oak riparian woods remaining anywhere.

"You come here and you see this habitat, you think, 'Wow! We've protected all these birds. We've really done something.' And we have," said Engilis, a bird-watcher since he was a boy growing up in Foothill Farms. "But this is far from healthy."

Birds clearly are drawn to the preserve to nest. Since 1995, researchers from Point Reyes Bird Observatory have documented nesting by 31 species of songbirds. Some do very well - generally, those that build deep "cavity" nests, such as the oak titmouse and downy woodpecker.

But the birds with shallow "open cup" nests are getting hammered. The nest watchers estimate that only 38 percent of song sparrow nests last year resulted in hatchlings, for example, and only 14 percent of Hutton's vireo.

Jeanne Hammond, a Point Reyes Bird Observatory staff biologist, said scientists believe that to sustain any given population of songbirds, eggs must hatch in at least 42 percent of nests.

"The hope was that we wouldn't find anything," Engilis said. "Instead, we've found rats at densities that are just mind-boggling."

In seven nights of trapping, the researchers nabbed 61 rats.

On camera, they caught a scrub jay, opossum and tree squirrel looting nests, but by far the most frequent robbers they found were black rats.

The researchers cannot say for certain that black rats are responsible for the songbird nesting failures, because they've lured the rats with artificial nests baited with quail eggs.

"It's hard to find a real nest, and when you do find a real nest, you really don't want to disturb the birds too much," said Desley Whisson, a vertebrate pest ecologist at UC Cooperative Extension.

What to do?

The scientists are leaning toward a proposal to poison the rats at the start of next year's nesting season, hoping to depress their numbers enough to give the birds a chance.
 

jerry d

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Boy, am I relieved to see they found the culprit to be rats. When I started reading this I was afraid they were gonna blame it on the moto duck. (hehe)

31 species of songbirds nesting in the area and they have a hard time finding nest???
 

Common Sense

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Wonder if they have anything to do with the decline of pheasants in the central valley?
 

Bossbrott

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When driving the early am the edges of the fwy in rice country are absolutley loaded with rats. I'm astounded any nests can survive.
 

Where's Bruce?

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Are they lead rats? Not yet.

They need to place those rings around the bases of tree that prevent rodents from getting up the truck to create sections of forest where the critters cannot transfer from tree to tree, creating a safe haven for the birds. I cannot imagine anything else plausible.
 

Bankrunner

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let me get this straight, these guys (who are most likely anti hunters) are leaning towards poisoning the rats. These poor rats are just little predators that feed on bird eggs in the spring. They are just doing what comes natural to them. Not unlike a Mountain Lion feeding on fawns in the spring.
I would bet that most of the song birds move on and successfully raise young in another location. They should at least do a much more extensive study to truly understand if the little creatures they plan on murdering are really even impacting the songbirds.
The poison part just makes me sick can you imagine the suffering of these poor little predators would go through. What about when their vicious poison traps takes out a nursing female, does she crawl back to her litter of newborns and die forcing the babies to then die a slow cruel death trying to suckle on her cold dead body? What if a hawk or a fox eats the poisoned rat?
These people are sick for even suggesting such cruel and inhumane measure.
These little creatures should be allowed to live their lives naturally, not be murdered by cold blooded killers!
Where is PETA when we need them.
 

eoats

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I like Bruce's idea & maybe looking into some ways to encourage more Raptors or other rat eating predators.

This crazy idea of spreading more poisons scares me.
 

Bayboy2020

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Had an old timer he thinks pheasants are declining because of rats robbing nests. He says that when they use to burn the rice it killed a large number of rats and now that we dont population is exploding
 

Bossbrott

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Put rings around the base of all trees and "set fire to this joint"!!!
 

Bankrunner

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Did you notice, the report said they caught some of these innocent creatures nosing around the eggs. They never said they ate any of the eggs.
Aren't these guys just herbivores, grains and seeds and such?
Stop the madness, we need more research to find the real culprit! For all we know they are just blaming an easy scapegoat!
https://www.youtube.com/watch?v=3YG4h5GbTqU
 
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P304X4

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Rats are scavengers that will eat anything that doesn't eat them first; there are even a few cases of rats attacking infants. I don't think that black rats are native to the US where the other critters mentioned are. That being said, this vermin should have been eradicated back when they were first discovered.
 

Bankrunner

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These are resilient creatures (The cut and pastes below are from wikapedia).
Maybe the answer is a combination of things. Tree rings, alternate food sources in the form of feeding stations during the spring nesting season and a unrestricted (day and night) rat season when only hunters are allowed on the preserve for three days a week. I bet night hunting black rats would be more gratifying than a ground squirrel hunt!

[h=3]Foraging behavior[edit][/h]As generalists, black rats express great flexibility in their foraging behavior. They are predatory animals and adapt to different micro-habitats. They often meet and forage together in close proximity within and between sexes.[SUP][14][/SUP] Rats tend to forage after sunset. If the food cannot be eaten quickly, they will search for a place to carry and hoard to eat at a later time.[SUP][7][/SUP] Although black rats eat a broad range of foods, they are highly selective feeders; only a restricted number of the foods they eat are dominant foods.[SUP][16][/SUP] When black rat populations are presented with a wide diversity of foods, they eat only a small sample of each of the available foods. This allows them to monitor the quality of foods that are present year round, such as leaves, as well as seasonal foods, such as herbs and insects. This method of operating on a set of foraging standards ultimately determines the final composition of their meals. Also, by sampling the available food in an area, the rats maintain a dynamic food supply, balance their nutrient intake, and avoid intoxication by secondary compounds.[SUP][16]

[/SUP]

[h=2]Predators and diseases[edit][/h][SUP]http://en.wikipedia.org/wiki/Black_rat#cite_note-Clark-16[/SUP]
The black rat serves as prey to cats and owls in domestic settings. In less urban settings, rats are preyed upon by weasels, foxes, and coyotes. These predators have little effect on the control of the black rat population because black rats are agile and fast climbers. In addition to agility, the black rat also makes use of its keen sense of hearing to detect danger and quickly evade mammalian and avian predators.[SUP][7][/SUP] Rats serve as outstanding vectors for transmittance of diseases because they have the ability to carry bacteria and viruses in their systems. There are a number of bacterial diseases that are common to rats, and these include Streptococcus pneumoniae, Corynebacterium kutsheri, Bacillus piliformis, Pasteurella pneumotropica, and Streptobacillus moniliformis, to name a few. All of these bacteria are disease causing agents in humans. In some cases, these diseases are incurable.[SUP][21]

[/SUP]

[h=2]Control methods[edit][/h]Large-scale rat control programs have been taken to maintain a steady level of the invasive predators in order to conserve the native species in New Zealand such as kokako and mohua.[SUP][25][/SUP] Pesticides, such aspindone and 1080 (sodium fluoroacetate), are commonly distributed via aerial spray by helicopter as a method of mass control on islands infested with invasive rat populations. Bait, such as brodifacoum, is also used along with coloured dyes in order to kill and identify rats for experimental and tracking purposes. Another method to track rats is the use of wired cage traps, which are used along with bait, such as rolled oats and peanut butter, to tag and track rats to determine population sizes through methods like mark-recapture and radio-tracking.[SUP][14][/SUP] Poison control methods are effective in reducing rat populations to nonthreatening sizes, but rat populations often rebound to normal size within months. Besides their highly adaptive foraging behavior and fast reproduction, the exact mechanisms for their rebound is unclear and are still being studied.[SUP][26][/SUP]
[SUP]http://en.wikipedia.org/wiki/Black_rat#cite_note-bacterial-21[/SUP]
In 2010, the Sociedad Ornitológica Puertorriqueña (Puerto Rican Bird Society) and the Ponce Yacht and Fishing Club launched a campaign to eradicate the black rat from the Isla Ratones (Rats Island) and Isla Cardona (Cardona Island) islands off the municipality of Ponce, Puerto Rico.[SUP][27][/SUP]
 

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