Worldwide, birds are disappearing as a result of a wide variety of threats. Anywhere from pesticides to habitat loss, from climate change to poaching, they are causing half of all bird species to decline in population. Billions of these amazing animals have died and are continuing to die each year. If you want to learn more about these threats and if you wish to help save the birds, read on.

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Habitat Loss

One of the biggest threats to birds is habitat loss. Humans have changed so much of the face of the Earth that now only 23% of the world’s land surface excluding Antarctica can now be considered wilderness. One of the main reasons for this huge loss of wilderness is the expansion of human agriculture. In fact, agriculture has impacted the existence of 74% of all birds worldwide, mainly for the worse.

This is because agriculture is one of the major driving forces for deforestation and 78% of all bird species can be found in forests. Already, there are half as many trees worldwide as there should be, most of which were removed in the past 100 years. Put into numbers, humanity has been the cause for the loss of approximately 3 trillion trees and that has greatly impacted bird species.

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Deforestation from agriculture is an especially serious problem in tropical regions where 91% of all terrestrial bird species are located. The Amazon Rainforest holds 14% of all known bird species by itself and it is under threat. 27% of it could be gone by 2030 alone.

However, the loss of birds in the tropics will also affect the rest of the world’s bird species. 40% of all known bird species are migratory and of all the birds in North America, half move south for the winter to Central America or South America if they are long-distance migrators. Some of these migratory species include Least flycatchers, Tennessee warblers, Indigo Buntings, Barn swallows, Broad-winged hawks, and Yellow warblers.

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Climate Change

Another major threat to world bird species is climate change, the worst environmental disaster in all of human history. It, along with other human-caused factors, is threatening 1 in every 8 bird species worldwide with extinction. In North America, that number climbs to 2 out of every 3 bird species.

That’s right. If nothing is done to help save birds and avoid the worst effects of climate change, then the majority of all bird species native to North America will be gone forever. The process has already begun. Since 1970, bird populations on the continent have fallen by nearly 3 billion adults.

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Besides impacting populations, how else is climate change affecting birds now? If you did not know before, warming global temperatures are changing bird habitats, the timing for migration and egg laying, and even the shape of some bird species' bodies.

Many North American birds have been shifting their ranges northward in response to warming temperatures but there are some species where this is not an option. On mountains for example, the only way for a bird to get to a colder location is to go further up. However, if climate change warms the planet too much they may run out of space and as a consequence go extinct.

Another problem that warming temperatures bring is the changing emergence time for certain insect species. For some insect species, they emerge en masse from wherever they were waiting in their larval stages and transform into flying adults. However, when temperatures become warmer earlier in the year because of climate change, they also emerge earlier in the year.

This is a big problem for migratory birds as they rely on arriving at their destination exactly when the most insects are around. If they come too late they miss the bounty and as a result, it becomes much harder for them to raise chicks. Migratory birds are slightly flexible though and they can change the timing of their migration slightly, but they cannot do it nearly fast enough.

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However, birds are not completely defenseless when it comes to climate change. Around the world, many bird species are on average getting smaller body sizes and longer wingspans. This almost certainly has to do with rising temperatures and likely helps the birds disperse body heat more effectively.

Threats to Penguins and Sea Birds

So far, this article has only mentioned terrestrial bird species. Penguins and sea birds are also birds. It turns out that climate change and other human-related factors are impacting these groups the worst of all.

In fact, sea birds are largely considered to be the most threatened group of birds globally. Penguins, while not as threatened, are still facing their own dramatic declines.

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In fact, more than half of all 18 penguin species are in decline. The most threatened species currently are the African penguin, the Galapagos penguin, and the yellow-eyed penguin. However, other species are to follow.

It is estimated that by 2100 nearly all emperor penguins will be gone as their habitat melts beneath them. They breed and rely on stable firm-packed ice near the Antarctic coast, something that will be in much shorter supply with warming temperatures.

Adelie penguins are predicted to decline by 30% by 2060 and African penguins have already experienced a global decline of 65% since 1989. The main reasons for these declining penguin populations are mainly loss of coastal habitat for the Antarctic penguins (not just the Adelies) and a decline in food sources. This is especially true for the African penguin as their main food source, sardines, have been overfished to the point of a population collapse and now they have turned to the more numerous gobies to subsist on. Gobies, however, are far less nutritious and this is the main reason for the African penguin population decline. Some experts have even estimated that the African penguin may go extinct within the next decade.

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For the penguin species that feed on krill, one of the most abundant species on the entire planet, the situation is also very serious. Antarctic krill populations have declined by around 80% since 1970. Krill faces multiple threats but the largest ones are climate change and overfishing. The 40% decline in phytoplankton numbers also probably does not help. The majority of vessels fishing for krill are from Norway.

However, the ramifications of a declining krill population stretch far beyond penguins. In fact, Antarctic krill are a keystone species which means they are absolutely critical to the environment they are part of. If a keystone species is removed from its ecosystem, then the entire ecosystem collapses and this is most certainly true for the krill.

Sea bird populations have declined globally by more than 70% since 1950. The top three threats to seabirds are invasive species (affecting 165 species), bycatch (affecting 100 seabird species but with a greater impact), and climate change (affecting 96 seabird species). These combined threats have resulted in the fact that 31% of all sea birds are threatened and nearly half of all species are declining. From by-catch alone, it has been estimated that hundreds of thousands of sea birds die each year.

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However, many of these bird species that are threatened with extinction can be saved. If warming is limited then 76% of the birds currently threatened by climate change in North America will be able to avoid extinction. This can only happen though, if enough people including you take action against climate change and for that matter all the other threats facing birds.

If climate change is limited to 2 degrees Celsius temperature rise, then the emperor penguin along with countless others can survive as a species. This is of critical importance and birds worldwide need your help now more than ever. Reduce your carbon emissions, support organizations helping birds, pressure your local government representative to take action against climate change, and raise awareness about the avian plight.

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Read Lucy Egans article "Humans' Catastrophic Effect on Birds and What You Can do to Help" to learn more about the direct human impacts on birds.