Deepwater Horizon

Source of pollution: 
oil platform/installation
Animals affected

Websites/blogs of TriState Bird Rescue Research Center; International Bird Rescue Research Center; Oiled Wildlife Care Network; US Fish and Wildlife Service

Total number of oiled birds counted: 
Due to the response effort and natural degradation and dispersion, the amount of oil now seen at sea is lower than previously. However the oil continues to affect wildlife, including sea and shore birds, marine turtles and marine mammals. Not all of the collected dead and debilitated live animals are externally oiled and not all dead animals covered in oil are confirmed to have been killed by the spill. Laughing gulls (2,981 collected) and brown pelicans (more than 800 collected)were the most heavily affected bird species. Bottlenose dolphins (a species already being impacted by an Unusual Mortality Event or UME)were, and continue to be, the most heavily affected cetacean species. Longer term impacts of the spill on dolphins from heavily oiled Barataria Bay, Lousiana are being monitored. As of 2013 low hormone levels, liver damage and low blood sugar have been noted in these animals, many of which are underweight as well. Research in the Gulf to monitor longer term effects of the spill will continue until at least 2015.
Terrapins,King Snake, various fish species
Species affected: 
Birds: Brown Pelicans, White Pelicans, Laughing Gulls, Northern Gannets, Night Herons, Cattle Egret, Snowy Egrets, Reddish Egret, Least Bitterns, Common Terns, Laughing Gulls, Brown Pelican, Sandwich Terns, Least Terns, White Ibis, Herring Gulls, Dunlins, Sanderlings. Sea turtles: Predominantly Kemp's Ridley. Marine mammals: Primarily bottlenose dolphins.
Number of birds released: 

Progress on permanently plugging the well - the well remains shut in with no oil flowing into the Gulf since July 15th. On 3 august, BP begun the "static kill" procedure, considered as potentially the ‘beginning of the end’ in stopping the flow of oil from the damaged well for good.

The idea is to use heavy mud and cement to push the oil back into its reservoir, more than two miles below the water's surface, a process which is expected to take several days. A week after the static kill is complete comes the next part of the two-pronged strategy: the "bottom kill" operation – a similar process involving the pumping of heavy drilling fluids and cement below the well, sealing it off from the top and bottom.

The static kill process was declared  successful on September 19, 2010.


UPDATE 2013:

Reports of ongoing sheens being seen around the Deepwater Horizon rig  raised concerns in 2012 that the Macondo well itself was once again leaking. Research into the source of the oil by a team from UC Santa Barbara and Woods Hole Oceanographic Institute determined that the leaking oil was coming from the sunken rig itself, where holding tanks still contain some oil.

This is good news in that the well itself is not leaking but it raises the concern that there will be ongoing leaking from the rig for some time.


This spill had a great impact on the international community. Worldwide, coastal authorities started reviewing their regulations regarding offshore drilling. With regards to oiled wildlife, responders had to deal some remarkable issues. There was the unusual high numbers of dolphins that stranded in the course of the spill, although a direct link with the spilled oil could not immediately be proven.

Another unique wildlife response activity was the recovery of tens of thousands of seaturtle eggs from turtle beaches, their transport to hatcheries, and the subsequent release of thousands of hatched juvenile turtles. Rehabilitation efforts were concerning seabirds (predominantly pelicans) and seaturtles. The challenges here were the continuous efforts that were required in the course of more than 5 months, including daily search and collection efforts, and treatment/rehabilitation activities in five coastal States.

Amount and type of oiled spilled: 
Crude oil; the US government announced a report on 2 August which estimates the total amount of oil spilt into the Gulf of Mexico as 4.9 million barrels (± 10%), in the 87 days it took to stop the flow from the wellhead. It is estimated that 26% (1.27 million barrels) of this oil is remaining on/just below surface as sheen or weathered tar balls, has washed ashore or been collected from shore, or buried in sand and sediments.
Wildlife Response: 

Wildlife response is carried out, led by the US Fish and Wildlife Service. Tristate Bird Rescue Research Centre leads the response to birds; Oiled Wildlife Care Network leads the response to sea turtles and marine mammals.

Below some presentations are provided on the wild animals collected and treated to date. The figures have been prepared by Sea Alarm on the based on data as are published every day by US Fish and Wildlife Service (and in the early days of the spill by IBRRC and OWCN).


Collection and treatment of birds

Figure 1: Intake of live oiled birds. Red line: cumulative intake (related to left y-axis); Blue bars: intake per day (related to secondary y-axis); green line: cumulative releases (related to left y-axis).

A total of 4914 birds have been collected to date. The proportion of oiled and unoiled animals according to US Fish and wildlife Service reports are as indicated in Figure 2.

Figure 2: Percentages of the birds categories Live and oiled, Dead and oiled, Unoiled and Pending, as provided by USFW

Based on the officially published data, the a release rate can be assessed as follows:

Figure 3: Release rate assessment. The yellow bars represent the reported number of released animals (NB: related to the secondary y-axis). The release rate (cumulative succesful releases against total bird intake) as presented here has been calculated by taking the total intake of 14 days ago (pink line; related to left y axis). It assumes that a bird admitted to a rehab centre spends on average ca. 14 days inside the centre before it is released.
Please be aware that this graph is based on speculation. The true release rates will be published in due time by those responsible for the oiled bird rehabilitation.

Collection and treatment of sea turtles.

Figure 4 : Registration of sea turtles. Blue: total cumulative number of sea turtles found, dead and alive; Green: total number of turtles collected with signs of external oil (dead and alive); Red: live turtles with signs of external oil on arrival (many of which in rehab centres).

A total of 843 sea turtles have been collected to date. The proportion of oiled and unoiled animals according to US Fish and wildlife Service reports are as indicated in Figure 5.

Figure 5: Percentages of the sea turtles categories Live and oiled, Dead and oiled, Unoiled and Pending, as provided by USFW

On July 11th (spill day 82) the authorities have started an attempt to transport sea turtle eggs from nests that were build on oil threatened to hatcheries in Florida. In total ca. 700 nests will be relocated. After hatching the hatchlings will be released from the unthreatened Atlantic beaches of Florida. Figure 6 presents the data that so far have been published by USFW on this operation.

Figure 6: History on transportation of eggs from nests to Florida and the release of hatchlings. The operation started on day 83 of the response


Collection history marine mammals

Figure 7: Registration of marine mammals (to date: only dolphins). Dark blue: total cumulative number of mammals collected in incident; Yellow: Total cumulative number of marine mammals collected with proof of external oil; Red: live stranded animals with external oil on arrival (immediately released or died on beach).

A total of  69 dolphins have been collected to date. The proportion of oiled and unoiled animals according to US Fish and wildlife Service reports are as indicated in Figure 8.


Figure 8: Percentages of the categories Live and oiled, Dead and oiled, Unoiled and Pending, as provided by USFW