Pesticides, not habitat loss, leading cause of grassland birds¯ decline - The Outdoor Community
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post #1 of 14 (permalink) Old 02-05-2018, 03:38 PM Thread Starter
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Pesticides, not habitat loss, leading cause of grassland birds’ decline

Pheasant hunting: Pesticides, not habitat loss, leading cause of grassland birds’ decline, study says

The loss of habitat is real in the corn belt, as are its potential effects on a host of grassland bird species, some hunted, some not.

But a new study concludes that declines of such birds, from the ring-necked pheasant to the horned lark, are more the result of pesticide use than any other factor, including habitat decline.

Below is a news release from the American Bird Conservancy. ABC didn’t fund this study, although it has contracted with one of the study’s principals, Pierre Mineau, for a related study that will be coming out in several weeks. “I won’t say that one’s a show-stopper, but it will get everyone’s attention,” said Robert Johns, spokesman for ABC.

Environment Canada funded this study, which notes Minnesota is the state exhibiting declines in the highest number of grassland bird species.

New Study Finds Pesticides Leading Cause of Grassland Bird Declines

(Washington, D.C., February 25, 2013) A new study led by a preeminent Canadian toxicologist identifies acutely toxic pesticides as the most likely leading cause of the widespread decline in grassland bird numbers in the United States, a finding that challenges the widely-held assumption that loss of habitat is the primary cause of those population declines.

The scientific assessment, which looked at data over a 23-year period – from 1980 to 2003 – was published on February 20, 2013 in PLOS One, an online peer-reviewed scientific journal. The study was conducted by Dr. Pierre Mineau, recently retired from Environment Canada, and Mélanie Whiteside of Health Canada.

The study looked at five potential causes of grassland bird declines besides lethal pesticide risk: change in cropped pasture such as hay or alfalfa production, farming intensity or the proportion of agricultural land that is actively cropped, herbicide use, overall insecticide use, and change in permanent pasture and rangeland.

“What this study suggests is that we need to start paying a lot more attention to the use of pesticides if we want to reverse, halt or simply slow the very significant downward trend in grassland bird populations. Our study put the spotlight on acutely toxic insecticides used in our cropland starting after the Second World War and persisting to this day – albeit at a lower level. The data suggest that loss of birds in agricultural fields is more than an unfortunate consequence of pest control; it may drive bird populations to local extinction,” Mineau said.

Many grassland bird species have undergone range contractions or population declines in recent decades. In fact, analyses of North American birds indicate that these birds are declining faster than birds from other biomes.

Habitat protection has long been considered a central pillar in efforts to stem the decline of grassland bird species, such as the Vesper Sparrow, the Ring-necked Pheasant, and the Horned Lark.

“We are still concerned about loss of habitat in agriculture, range management, and urban development,” said Cynthia Palmer, manager of the Pesticides Program at American Bird Conservancy, a leading U.S. bird conservation organization. “This study by no means diminishes the importance of habitat fragmentation and degradation. But it suggests that we also need to rein in the use of lethal pesticides in agriculture, and that we need to be especially careful about any new pesticides we introduce into these ecosystems such as the neonicotinoid insecticides. It reminds us that the poisonings of birds and other wildlife chronicled a half century ago by famed biologist and author Rachel Carson are by no means a thing of the past.”

The researchers focused on the extent to which lethal pesticides, such as organophosphate and carbamate insecticides, are responsible for the decline in grassland bird populations. The study found that lethal pesticides were nearly four times more likely to be associated with population declines than the next most likely contributor, changes in cropped pasture – an important component of habitat loss associated with agricultural lands.

The publication says that “…..large quantities of products of very high toxicity to birds have been used for decades despite evidence that poisonings were frequent even when products were applied according to label directions.”

The authors argue that only a small proportion of total cropland needs to be treated with a dangerous pesticide to affect overall bird population trends. The production of alfalfa stands out for its strikingly high chemical load, constituting the third highest lethal risk of any crop based on toxic insecticide use. Pesticide drift from croplands is also affecting birds that favor the adjoining grasslands.

Using data from the U.S. Geological Service Breeding Bird Survey for the years 1980 to 2003, the study found that declines of grassland birds were much more likely in states with high use of toxic insecticides lethal to birds. The species with the greatest number of declines included the Eastern Meadowlark (declining in 33 States), the Grasshopper Sparrow (25 States), the Horned Lark (25 States), the Ring-necked Pheasant (19 States) and the Vesper Sparrow (18 States). The states with the greatest number of declining grassland species were Minnesota (12 species), Wisconsin (11 species), and Illinois, Michigan, Montana, Nebraska and New York, all with nine species.

The current study relies on pesticide data from the 1980s and early 1990s, a time when organophosphates such as diazinon and chlorpyrifos, and carbamates such as carbofuran and methomyl, were still largely in vogue. Since that time, a new class of insecticides, the neonicotinoids, have soared to the top of global pesticide markets. Unfortunately, a major toxicological assessment soon to be released by American Bird Conservancy puts to rest any notion that birds and other organisms will fare much better under the new pesticide regime.
» Pheasant hunting: Pesticides, not habitat loss, leading cause of grassland birds? decline, study says

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post #2 of 14 (permalink) Old 02-05-2018, 04:18 PM Thread Starter
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A very thorough 2017 , NCBI, NIM, NIH study on pheasant population declines in California;

Pesticides, Predators, Crop types, Ag Practices, Land Use, Weather, It's all here....

[B]Long‐term and widespread changes in agricultural practices influence ring‐necked pheasant abundance in California[/B]

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post #3 of 14 (permalink) Old 02-05-2018, 04:43 PM
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Grouse are also on the decline, I do not think they would be greatly impacted by these pesticides. As I have said before all small game has been going down in numbers since predators have risen in numbers.
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post #4 of 14 (permalink) Old 02-05-2018, 06:33 PM Thread Starter
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Check out the 2017 California study. They look at detailed studies on various types of predators and their affects on pheasant populations too.
No doubt they have a significant effect especially when you combine the loss of the variety of other species they used to prey on.
I was surprised that they noted a significant affect from various types of crows and ravens on ground nesting bird's eggs.
Also they report a significant negative effect on pheasant populations in the presence of wild turkeys.

I think that there might be a bias among many wildlife researchers to down play the effect from raptors maybe because in the past their populations dropped so low.

After Oregon, California was one of the earliest states to see success with high populations of wild pheasants in the U.S. in the past

The effects that varied substantially across regions were those related to competitors and predators, receiving relatively less support than other variables but nonetheless substantiated by data. The strongest of such effects was corvid abundance, notably important in the North Central, Bay Delta, and South Coast regions. Corvid populations have significantly increased across western United States (Sauer et al., 2014) in response to ample anthropogenic resources (Boarman, Patten, Camp, & Collis, 2006; Marzluff, McGowan, Donnelly, & Knight, 2001). In California, corvid populations have increased most dramatically along coastal areas. Increases in raven numbers have been shown to negatively impact nesting success of other Galliformes (Coates & Delehanty, 2010). Raptor abundance also garnered support from these data, and predation by raptors on adult pheasants can be significant in some areas (Kenward, Marcström, & Karlbom, 1981) including northern California (Grove et al., 2001). However, negative effects related to increased avian predators (i.e., ravens and raptors) are likely exacerbated by lack of adequate cover remaining in intensively farmed cropland, low‐quality environments in which populations are more sensitive to predation (Evans, 2004). Interestingly, our results indicated a negative relationship between pheasant and wild turkey, another non‐native game bird species to California. This could be an indication that the two species respond differently to the reported land use changes, or could indicate a form of interspecific competition. To our knowledge, competition between these species has not been reported previously and warrants well‐designed experimental study.

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post #5 of 14 (permalink) Old 02-07-2018, 09:54 AM
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Those are some interesting articles. I tend to belive them. More than just blaming habitat loss.
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post #6 of 14 (permalink) Old 02-07-2018, 07:10 PM
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Kind of off topic but bird related.
I have noticed a very sharp decline in any birds visiting my feeder. I know it's been cold but I don't recall this level of inactivity ever before. Even the crows are absent.

Good night Chesty, wherever you are......
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post #7 of 14 (permalink) Old 02-07-2018, 07:26 PM
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What I have noticed is the lack of Mocking birds and cat birds which are both insect eaters over the last few years at my place.

When you are up to your butt in alligators, it is hard to remember your intent was to drain the swamp. Stay focused!
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post #8 of 14 (permalink) Old 02-08-2018, 01:29 PM
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Around here the black-cap chickadees and American gold finch populations have been extremely low, almost none existent, the past few year though they might have increased ever so slightly last year.

I suspect that to be west nile related, but it certainly could be a combination of factors. I have no doubt the high levels of pesticide use would be a factor for any number of bird species.

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post #9 of 14 (permalink) Old 02-08-2018, 01:51 PM
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I have chickadees, nuthatches and titmice and Juncos all year and am far from big woods, I just have a long bank with lots of shrubs and a Redbud and a huge blue spruce. However my gold finch population is way down in the spring and summer but I have a ton of house finches which are not native to the US all year long.

When you are up to your butt in alligators, it is hard to remember your intent was to drain the swamp. Stay focused!
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post #10 of 14 (permalink) Old 02-08-2018, 04:11 PM
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I have noticed a decline in the amount of chickadees I have been seeing when out hunting. Plenty of goldfinches and purple finches around my area but the chickadees seem to be increasing around the house/bird feeders. Just not seeing any in the woods when hunting like I use to. I noticed an increase in the number of crows over the last few years. Also the amount of sparrows I am seeing seems to also be on the up swing.
Of note there has been a large increase in the number of robins I have been seeing around. ( not yet this time of year but when they arrive they seem to always come in abundance. Robins are looked at as carriers for WNV. ( Thank you Lost for pointing that out to me and pointing me in the right direction to read up on robins and WNV) Waugh!

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