Ethics of feeding garden birds (1 Viewer)

[Nightranger]

Food supplementation should also produce changes in
territorial behavior, since this trait is often coupled with
resource availability. During winter, flocks of blackcapped
chickadees defend foraging territories; however,
this system often falls apart when food supplements are
provided, as flocks frequently cross territorial boundaries
to visit feeders (Wilson 2001). Alternatively, territorial
behavior can increase with provisioning as the presence
of clumped or high-quality food allows birds to engage in
costly resource defense behaviors. When provided with
food, Carolina wrens (Thryothorus ludovicianus) spend
more time defending territories by singing (Strain and
Mumme 1998). One of the most likely explanations for
these differences among territorial responses to supplements
is the defensibility of the resource, as food presented
in small amounts in multiple areas will give the opportu-
nity for larger or more aggressive individuals to dominate
the food supply. For example, older adult Egyptian vultures
(Neophron percnopterus) exclude younger birds when
individual carcasses are provided. However, when food is
provided in a more scattered fashion, individuals can no
longer defend the supply and no age group dominates
feeding (Meretsky and Mannan 1999).

There is a very good reason why we do not see this in the UK, which I discussed further up the thread but strangely enough, we would expect this effect to be seen more often here in the UK than in continental Europe where the same species are nomadic or migratory. This is a useful paper that Alf has posted and I am looking for anything tht can help in discussing ideas at the beginning of the thread.

 

[AlfArbuthnot]

More relevant papers, but worth noting that they were before the recent studies linking birdfeeding to the finch epidemic.

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Birdfeeding is a massive open-ended experiment with mostly unknown consequences (good or bad):

Feeding birds in our towns and cities: a global research opportunity (2008)
Jones & Reynolds, Journal of Avian Biology 39:262-273.
http://onlinelibrary.wiley.com/doi/...sCustomisedMessage=&userIsAuthenticated=false

Abstract: Wild bird feeding is one of the most common forms of human-wildlife interactions in the Western world. Originally a practice providing nutritional assistance to over-wintering birds, especially in more northern latitudes, birds throughout the cities of the world are now provided with considerable amounts and a variety of foods year-round. Despite the global nature of the practice, remarkably little is known about the outcomes and implications of what may be seen as a supplementary feeding experiment on a massive scale. Although many claims are made about the benefits of feeding, there are growing concerns about the spread of disease, poor nutrition, risk of dependency and many other important issues. Constructive debate among increasingly vigorous proponents and opponents is currently constrained by a lack of reliable information. Here we argue that bird feeding provides an important, if challenging, opportunity for fundamental research in urban ecology.
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Birdfeeding changes bird populations in a UK city:

Garden bird feeding predicts the structure of urban avian assemblages
Fuller et al. (2007) Diversity and Distributions 14:131-137.

ABSTRACT
Households across the developed world cumulatively spend many millions of dollars annually on feeding garden birds. While beneficial effects on avian assemblages are frequently claimed, the relationships between levels of garden bird feeding and local avian populations are unknown. Using data from a large UK city, we show that both avian species richness and abundance vary across different socioeconomic neighbourhood types. We examined whether patterns in bird feeding could explain this variation. The density of bird feeding stations across the urban environment was strongly positively related to avian abundance, after controlling for differences in habitat availability. This effect was almost exclusively driven by the abundance of those species known to utilize garden feeding stations frequently. In contrast, the density of feeding stations had no effect on avian species richness. We also examined variation in the proportion of households in different communities that provide food for birds, a factor that is not correlated with feeder density. The prevalence of bird feeding across different neighbourhoods declined as socioeconomic deprivation increased, and increased with avian species richness and abundance. Our results suggest that the provision of supplementary food for birds by multiple landowners across a city can impact the status of urban bird populations. The potential for harnessing these actions for conservation needs to be explored.

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Birdfeeding in the UK has changed the course of Blackcap evolution:

(jargon-free summary: http://newswatch.nationalgeographic.com/2009/12/06/feeding_birds_shown_to_impact/ )

Contemporary Evolution of Reproductive Isolation and Phenotypic Divergence in Sympatry along a Migratory Divide
Rolshausen et al. (2009) Current Biology 19:2097-2101

Summary
Understanding the influence of human-induced changes on the evolutionary trajectories of populations is a fundamental problem 1 and 2. The evolution of reproductive isolation in sympatry is rare, relying on strong selection along steep ecological gradients 3, 4, 5, 6 and 7. Improved wintering conditions owing to human activities promoted the recent establishment of a migratory divide in Central European blackcaps (Sylvia atricapilla) 8 and 9. Here, we show that differential migratory orientation facilitated reproductive isolation of sympatric populations within <30 generations. The genetic divergence in sympatry exceeds that of allopatric blackcaps separated by 800 km and is associated with diverse phenotypic divergence. Blackcaps migrating along the shorter northwestern route have rounder wings and narrower beaks and differ in beak and plumage color from sympatric southwest-migrating birds. We suggest that distinct wing and beak morphologies are ecomorphological adaptations resulting from divergent, multifarious selection regimes during migration. We hypothesize that restricted gene flow accelerates the evolution of adaptive phenotypic divergence toward the contrasting selection regimes. Similar adaptive processes can occur in more than 50 bird species that recently changed their migratory behavior 10 and 11 or in species with low migratory connectivity. Our study thus illustrates how ecological changes can rapidly drive the contemporary evolution of ecotypes.

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[jpoyner]

I stop feeding once the birds begin breeding and only start again once the weather gets cold. I don't believe wild birds need or should be supplementary fed during summer at all. Funny how it's those selling the food that seem to push the idea they need feeding all year round....they don't, in fact if anything it does more harm than good, disease causing bacteria around the feeders are far more likely during warmer weather.

 

[Trystan]

I stop feeding once the birds begin breeding and only start again once the weather gets cold. I don't believe wild birds need or should be supplementary fed during summer at all. Funny how it's those selling the food that seem to push the idea they need feeding all year round....they don't, in fact if anything it does more harm than good, disease causing bacteria around the feeders are far more likely during warmer weather.

On the other hand, and I have no evidence to back this up, I stopped feeding over summer this year and now I don't have bullfinches anymore, I can't help wondering if I would have if I'd kept feeding.

 

[Nightranger]

On the other hand, and I have no evidence to back this up, I stopped feeding over summer this year and now I don't have bullfinches anymore, I can't help wondering if I would have if I'd kept feeding.

Probably not Trystan, we have a small population around where I live or at least, nearby on my local patch but they are often difficult to pin down. We have had them visiting the garden and I am pretty sure I know where they breed but that does not guarantee I can see them on a given day. I am not sure what their foraging territory size is like but it must be quite large compared to say, the house sparrow.

 

[birdmanchan]

Couldn't disagree more!!!

Choosing a natural seed or even providing sensible left overs is taking away from nobody.

Studies in the UK have shown that the population of finches is directly affected by the yield of Ash Seed. Recent years have seen a decline in Ash trees, namely from Ash Dieback......So feed away my friends!!

 

[WBF AH]

One of the reasons people buy bird feed to feed birds in their garden is the belief that they are helping birds. This is especially true in winter, a time when food is scarce, and when some birds supposedly need our help or they would die. This belief is sometimes accompanied by an argument that since humans have encroached so far onto wild nature and what used to be the birds' natural feeding grounds, that it is only right that people give something back.

I would argue that growing seed in one part of the world to feed birds in another is just displacing habitat destruction elsewhere, and is far less efficient than simply not feeding birds, and therefore having less industrial chemical monocrop agriculture overall. If we like seeing a few birds in our garden at the expense of greater bird populations elsewhere, then garden bird feeding makes sense. But if we take a broader view, then cultivating land to grow crops which are then shipped around to feed certain favoured populations makes no sense. It is just accelerating the process of taking resources away from nature and using them them in wasteful, destructive agriculture.

Fat balls are a fine example: taking tracts of land to grow grain, to feed cattle, to produce suet, to feed garden birds is possibly the most wasteful way of feeding birds we could come up with. Spraying bird pests with Starlicide to protect sunflower crops destined for birdseed is a contradiction hopefully obvious to most. But beyond that, the whole idea of using agriculture to feed wild birds is problematic if we take a wider view. And how is it possible to care about birdlife and bird populations if we don't take a wide view?

Discuss.

It's nice to see suppliers are switched on to these types of discussions
http://www.wildbirdfeeders.co.uk/all-about-birds/birding-articles/the-great-debate